The Soldier that Guarded President Lincoln has a connection with Alabama

William F. [Flavius] Cost, 11th Cavalry
The Soldier That Guarded President Lincoln
Researched and donated by Andy Bryant

William and his Family:

William Flavius Cost was born July 26, 1837. He died May 23, 1881. By records of the Loudoun County, Virginia 1850 Census, William was 13 years old in that year. He had a brother named Thomas Jackson; a brother named John Mortimor; a sister named Emily Eugenia; a sister named Ellen Francis. There was an infant sibling who most likely died at birth as there are no recorded dates of birth and death other than “infant Cost”.

William was the son of Jonathan Martin Cost [B-1813, D-?] and Bathasa Cost who was his mother [B-?, D-?]. His brother Thomas was born in Lovettsville, [Loudoun County] Virginia in March of 1833, so it is assumed that is where William was also born there.

His Grandfather’s name was John Cost [B-1789, D-1856] of Frederick, Maryland. His GGrandfather’s name was Thomas Cost [B-1754, D-?] of Loudoun County, Virginia. His G, G, Grandfather’s name was Johann Henrich Kost [B-1723, AFT-1763] of Germany. Therefore, William F. Cost was of German decent.

 (All above, Ref:

Loudoun County, Virginia

Loudoun_County,_Virginia map

[William’s service in the Civil War will be noted latter in my story]

At some point in time after William F. Cost survived serving in the Civil War and was discharged, he married a girl named Malinda E. Potterfield [Born in 1840] on December 17, 1868 in Loudoun County, Virginia. ( It is not known if he knew her while growing up; or met her before he joined the military or if he met her after serving in the military. [It is only my personal opinion]; I feel William met Malinda before his military service and they were possibly childhood friends or maybe even “sweethearts”.

Sometimes between the dates when William and Malinda were married in Loudoun County, Virginia in 1868 and 1870, they moved to Florence (Lauderdale County), Alabama. As recorded in the 1870 U. S. Federal Census, they were listed as living there in “Township 1, Range 12, Lauderdale, Alabama”. At that time, according to the June 16th, 1870 census, William was listed as being 34 years old; he was a “farm hand” and he was listed as being born in “Virginia”. Also, his wife, Malinda, was listed as being 27 years old; she was listed as “Keeping house” and she was listed as being born in “Alabama”.  (Ref:  

Lauderdale County, Alabama

Lauderdale_County_Alabama map

There is a question in my mind at this point about Malinda’s birth place. Was she born in Alabama as the census mentioned, or was she born in Virginia and it was written by mistake by the 1870 census taker?  It is noted in the Loudoun County 1860 Census that Malinda E. Potterfield, who was listed as 20 years old, was living at home with her father; Jacob Potterfield [45 years old] and her mother Sarah A. Potterfield [42 years old]. (Ref:

Also, according to this same census, she was the oldest child of seven children the Potterfields had. There is listed; a sister named Sarah B. [19 yrs.]; a sister named Caroline [17 yrs.]; a brother named Revandy J. (sp) [10 yrs.]; a brother named Othello M. [7 yrs.]; a sister named Ann R. [4 yrs.] and a sister named Lillian R. [1 yr.]. (Ref:

As the writer of this family history part of William F. Cost’s story, I have found no record of him and Malinda having any children. The next recorded information that I find regarding William is located in the “LauderdaleCounty Alabama, Cemeteries-Township 3 and Range 11” records. Contained there in the “Florence City Cemetery”, he is listed as being buried in “Section, F-5 and Row-08” of that cemetery. That record states that a

Cost, W. F.” was born “26 July 1837” and died “23 May 1881”. This, of course, is the same, William Flavius Cost who was the husband of Malinda E. Cost.


The next record I have is of Malinda E. Cost. She is “mistakenly” named as “Mary E. Cash” in the “AlabamaMarriage Collection 1800-1969” record. That record stated that she re-married a man named Robert E. Coburn on the 26th of March, 1884. They were listed as being married in Lauderdale County, Alabama. (

The 1900 U. S. Census of Florence (Lauderdale County), Alabama, states that Malinda E. Coburn [age 60] lived with her husband Robert E. Coburn [age 56]; Sallie Coburn [age 29]; Oella Coburn [age 27]; Emmel Coburn [age 25] and Arthur L. Coburn [age 20]. This census was dated the 18th and 19th of June, 1900. (

There are two items recorded on this same 1900 U. S. Census that raises some questions in my mind. I backtrack to my concern of not finding any records of William and Malinda having children. Listed on this 1900U. S. Census are two columns. One is headed as “Mother of how many children.” Marked in that column on Malinda’s line is “3”. The second heading is “Number of these children living.” Marked in that column on Malinda’s line is “1”. (Ref:  The haunting thoughts that I now have are: First of all, did William and Malinda have children or not? Second, if they did have “3” children and two of them died, why are these records not found after extensive research?

The next record I find regarding Malinda E. (Cost) Coburn is the 1910 U. S. Census. Malinda is shown as being 70 years old; living with her 2nd husband, Robert E. Coburn, [age 64] and an Oella Coburn, [age 35]. They are all listed as living in “Florence Ward 4, Lauderdale, Alabama”. On this same 1900 U. S. Census, it states that Malinda’s “Place of birth of this person” column states “Virginia”; “Place of birth of Father of this person” column states “Virginia”; “Place of birth of Mother of this person” column states “Virginia”. This is clear evidence that proves that Malinda and her Father and her Mother all were born in Virginia. (

After Malinda Elizabeth Potterfield married William Flavius Cost and he died in 1881, she re-married Robert E. Coburn in 1884. Then on the 22nd day of August in 1917, Malinda Elizabeth Potterfield (Cost) Coburn died in Florence (Lauderdale County), Alabama. Malinda’s second husband, Robert E. Coburn, died on the 4th day of April, 1954 in Lauderdale County, Alabama. (Ref:

Malinda’s record of place of burial is recorded in the “Lauderdale County, Alabama, Cemeteries-Township 3 and Range 11” records. Contained there in the “Florence City Cemetery”, she is listed as being buried in “Section, F-5 and Row-8” of that cemetery and in the same location as her first husband William. That record states that a “Coburn, Malinda E. Cost” was born “13 Jan 1840” and died “23 Aug 1917”. This, of course, is the same Malinda Elizabeth Potterfield who was the wife of William Flavius Cost.


Her love for William was so strong and enduring that after 36 years after his death, Malinda was buried next to him in Florence (Lauderdale County), Alabama. Her headstone, yet so small and insignificant as compared to William’s larger one, symbolizes volumes. They are now, at last, finally together. (Ref: pictures of gravesite)

William and the Civil War:

I have found no records regarding William F. Cost from the 1850 Loudoun County, Virginia Census [when he was 13 years old] until the time of his military service.


In 1860, he would have been 23 years old. In 1861, there was talk of rebellion between some of the southern states and the northern states. Washington D. C. was the center of the known United States of America at that time. William lived just across the river in Virginia and I am assuming he felt in his heart to support the Northern cause. Therefore I can only imagine wherever he was, he moved his way towards the Washington area in order to keep up with the latest developments.

When the year of 1861 began, there are a number of things that could have happened with William. [I have found no exact records to justify what I foresee could have happened.] However it is documented William served in a total of three Union military units during the Civil War. They are listed (in order of service) as:

1. B Company, 1st Battn. D. C. Militia Volunteer Infantry (Ref.; M538 roll 1)

2. K Company, 11th New York Calvary (Ref:; M551 roll 29)

3.  I Company, 20th Veteran Reserve Corps (Ref:; M636 roll 7/8) 

 The first unit he served with: B Company, D. C. Militia Volunteer Infantry

After a long and prestigious military history, this unit; which was originally constituted on the 3rd of May 1802 in the District of Colombia Militia as the First Legion, Columbian Brigade is known today as the 372nd Military Police. (Ref:

In January and February of 1861, Washington, D. C. volunteer foot companies of the old unit were reorganized with personnel who supported the Union. They were formed into the 1st through the 8th Battalions. They were mustered into Federal service in April 1861. They were mustered out of Federal service in July of 1861. They reorganized and mustered back into Federal service that same July 1861 to October of 1861. On the 26th of February, 1862, they were reorganized again. It is at time period I believe William F. Cost joined the unit. It would have been for a three month period; until 26 May, 1862.

The 1st District of Columbia Infantry Regiment [Pvt. William F. Cost was a member] was employed in the defense of the capital and mainly the guarding of President Abraham Lincoln and his family. They were more or less known as “Provost Marshals”. President Lincoln did not stay at the White House each night as he did not like the hot temperature and the “Capital environment”. Therefore, he would travel each day by carriage back and forth from the capital to the Soldiers’ Home.


 On March 7th, 1861, Pres. Lincoln visited the home for the first time. It was located near the National Cemetery and about 2 or 3 miles from the Capital Building. On July the 11th, 1861, Mary Lincoln wrote to her friend to tell her the Soldiers’ Home was “….a very beautiful place.” and that her family would be moving there in three weeks. President Lincoln was guarded at both the Capital and the Soldiers’ Home daily.


During the early part of 1862, there were other military units recruiting in the District who served elsewhere in Washington and the surrounding areas under their own states’ designations. They were the 3rd Maryland Infantry, 1st Maryland Cavalry, 11th New York Cavalry, 71st Pennsylvania Infantry, and the 3rd Pennsylvania Cavalry; all had a company or more recruited in Washington.

(Ref: GAR, Department of the Potomac, Roster of Departments, 1888, p.54)………………….

When William’s service time expired with the D.C. Militia Infantry in May of 1862, being the good soldier he was, he looked to join another unit. I feel comfortable that he liked the looks of the cavalry units, but how he made his choice which one to join, was known only to him. Finally, on the 20th day of August, 1862, he joined the 11th New York Calvary. He was assigned to B Company. At that time, William was 25 years old.

The second unit he served with: K Company, 11th New York Calvary

The origins of this New York Calvary unit began in December of 1861, to May of 1862 on Staten Island, New York. It was commanded by Lt. James B. Swain. He nicknamed his new Calvary unit “Scott’s 900”, after his good friend Thomas A. Scott, who was at that time, the Assistant Secretary of War. (Ref:

Each company of the unit was formed in different New York cities. Company K (which William F. Cost later joined) was formed in the cities of; New York City, Auburn, Union Springs, Springport, Ausable Forks, Jay and Senneca Springs. The 11th New York left the State on May 5, 1862 for duty in guarding Washington, D.C. (

Upon their arrival in Washington D. C. in early May of 1862, the 11th New York, as I mentioned earlier, started recruiting men from the D. C. area; in order to fill their allotment of men. As recorded from his muster roll, William F. Cost (25 years old) joined their unit on the 20th of August, 1862. He was signed up for three years service. He was officially mustered in on the 28th of August as a Private in Company K of their unit.


The 11th New York was assigned to duty in the defenses of Washington, D. C. until March of 1864. While there, some members of different companies preformed many different duties. Some were assigned to stop Confederate recruitment around the Capital area; some were assigned to guard railroads and bridges; some were assigned to guard the ships and harbors; some were assigned to raid into Virginia to ward off the enemy and mainly, some were specially selected to guard and escort President Lincoln as he traveled back and forth from the Soldiers’ Home to the capital. (Ref:

Because Pvt. William F. Cost had previously guarded the President in his earlier D. C. Infantry duties, it would be only natural; due to his previous experience his new duty would be to continue doing so as a soldier in K Company. As a Calvary soldier with the 11th NY, William would have a carbine as his main weapon to carry. In his case, he carried a Burnside Carbine rifle. As a matter of fact, a Burnside Carbine with the serial number 18390, even though no exact record of its assignment is found, has the name

 “W F Cost” carved into the right side of the stock and the initials “B G H” carved into the left side of the stock. It is presently owned by this writer. Records from the Springfield Research Center show that Burnside Carbines with the following serial numbers were issued to the following units:

18358 — CO C 12th NY CAV

18365 — CO E 4th WISC VOL CAV

18390 — [With “W F Cost” & “B G H” carved into the stock and is owned by this writer]

18396 — CO C 12th NY VOL CAV

18406 — CO C 12th NY VOL CAV


As I have completed much research on the 11th New York Calvary, and the rosters of the same, I find that a soldier named Pvt. Benjamin G. Hill was in the same K Company, 11th New York Calvary as Pvt. William F. Cost. It is only my assumption these two soldiers became good friends. They both were from Virginia, but it is not documented as to whither they knew each other or not before they enlisted. One thought I have is; due to the fact they both were assigned to K Company and they enlisted only two days apart; [William on 20 Aug. and Benjamin on 22 Aug., 1862] leads me to believe they did not know each other before joining and quite possibly, they became good close friends. Be as it may, history proves they both carved their mark on the same Burnside Carbine rifle which has the serial number 18390.

[I will have more information and history on Pvt. Benjamin G. Hill in another story.]

The 11th New York Calvary continued patrolling, guarding and fighting in and around the Washington D.C. area completing their various duties. Most of them were involved in about ten or eleven different battles; as recorded in their historical profile.


In March of 1864, the majority of the 11th NY was ordered to the Department of the Gulf. There were a few members of the unit who stayed in Washington to keep guard over President Abe Lincoln and the Capital. Pvt.William F. Cost was one of them who stayed there. This is reflected by records of him serving in a third military unit which was stationed in Washington at the same time the rest of the 11th NY was in the Gulf and later; in Tennessee. Also, when William was mustered out of service of the 11th NY, he was done so by being “on Detachment” as was noted in the “explanation” section of his muster out roll dated the 8th day of May, 1865. Most all of the 11th NY mustered out of service in Tennessee on the 30th day of September in 1865. William was mustered out of the 11th New York Calvary four months and twenty-two days before the rest of his unit did. This means that Pvt. William F. Cost was not “physically” in Tennessee with the rest of the 11th New York. (Ref: & (Ref:  

The third unit he served with: I Company, 20th Veteran Reserve Corps

The Veteran Reserve Corps was originally called the “Invalid Corps”. It was created in April of 1863 by the War Department and was composed of different units and company numbers. Each one had its’ own assignments. The “Invalid Corps”, as it was originally named, was created when the amount of wounded and disabled soldiers became so numerous and many did not return to service duty as they were supposed to. These “convalescent wounded and feeble men”, who were still fit for minor duties such as cooks, nurses, hospital attendants, guards and other “light duties”, were formed into 2 “battalions”. The soldiers who could carry arms and perform garrison duty were assigned to the 1st Battalion. Those who could not do so, were used only in hospital service. Those men were assigned to the 2nd Battalion. Thus, all were called the “Invalid Corps”. On March the 18th of 1864, the Invalid Corps was re-named the “Veteran Reserve Corps”.


On the 14th day of April, 1865, President Abraham Lincoln was shot and killed. The city was in a shamble. The Union, torn apart due to the war, was disarrayed and in turmoil. The Nation was pressing for action. Security was at an all time high. The leaders and commanders of the Armies were hard pressed to find the “Killers and Conspirators” as quickly as they possibly could. Soldiers from every unit were being “sought” to help find those that killed President Lincoln. Pvt. William F. Cost, who had been helping to guard the President, I am sure, wanted to do his part to help. As he was due to get mustered out of the 11th New York in a couple of months, I feel that is why he was able to muster out early on the 8th of May, 1865.(

It is at this time period I feel he joined the Veteran Reserve Corps. By doing so, he would be in a position to help with locating the “Killers”; as many of that unit was in the process of investigating people as being co-conspirators. John W. Booth was captured, shot and died 12 days later on the 26th day of April, 1865.

William F. Cost, who mustered out of the 11th New York Calvary as a Private, was signed into I Company, 20th Veteran Reserve Corps as a Sergeant. (Ref: )

I am sure that, as a soldier who guarded President Lincoln, Sgt. William F. Cost preformed his duties with the utmost diligence and expertise. I am also sure he was highly involved with the capturing, guarding and possibly involved with the hanging of the co-conspirators. After their trials and convictions by military courts, they all were hanged by the military on the 7th day of July, 1865. I feel strongly that Sergeant William F. Cost, I Company, 20th Veteran Reserve Corps, was present that day and during the funeral processions of President Abraham Lincoln because it is on records that the Veteran Reserve Corps were in attendance. (

I can find no record of exactly when William was mustered out of I Company, 20th Veteran Reserve Corps. I clearly assume he stayed past the hanging date of the conspirators; which was on the 7th of July, 1865. I do know from records that the Veterans Reserve Corps started to disband and muster out between the dates of June 15th, 1865 until the 21st of November, 1865. (Ref:

The facts I know that are from historical records are:

A. William Flavius Cost was in Washington, D. C. guarding President Abraham Lincoln and his family between 1862 and through the summer of 1865.

B. William Flavius Cost was in Washington D. C. when President Lincoln was assonated. 

C. William Flavius Cost was present for the capture, the trials and the hanging of all of the co-conspirators of the murder of President Lincoln.

D. William Flavius Cost was a very patriotic, loyal, and devoted soldier of the Federal Forces during the Civil War.

E. William Flavius Cost served his country with honor and dignity.

F. William Flavius Cost carried and carved his name in a Burnside Carbine rifle [serial number – 18390]; that I am very proud to research and care for.

I hereby give Sergeant William Flavius Cost the praise and dignity that he very well and past due deserves by honoring him with this; His Story.

I also dedicate it to his descendent Mr. Gary Cost, Ohio; who has helped me with the research, support, encouragement and friendship he has given me during these past months. Also, to “my friends” in Alabama for all of their help, I say; thank you!

Researched, composed and written by me this 11th day of April, 2008

E-Signed: Andy Bryant


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