Quite a few Lawrence family genealogies contain a case of mistaken identity that continues to be perpetuated. It's an easy mistake to make because two Williams married two Sarahs who were all contemporaries and both couples lived in Montgomery County, Virginia, but not at the same time. 

In my family tree there are several men named William Lawrence. The first William, born in 1764, was the son of Elder John Lawrence. Elder John, and his family moved from Dutchess County, New York to Montgomery County, Virginia after the American War of Independence. Elder John had two other sons named Thomas and John. 

According to some of William's descendants, he married a woman named Sarah (aka Sally) in Montgomery County, Virginia in 1784. Sarah's maiden name is not known, but is frequently said to be "Booth." It is the name "Booth" that I believe to be the case of mistaken identity. The assumption is made that Sarah Booth (b. abt 1816) married William Lawrence (b. 1764) who was the son  of Elder John. However, this is not the case.

In 1812 William and at least four of his children, and presumably his wife, relocated to Rockcastle County, Kentucky leaving the rest of the Lawrence family in Virginia. We know that William was married to someone named Sarah because she and William are listed in a death register as the parents of Tartulas Lawrence who died in Rockcastle County, Kentucky on 7 Jun 1876. With the exception of the record of Tartulas' death, I am unaware of any documents that mentions William's wife by name. A daughter of William and Sarah, Catherine Lawrence Carson, disclosed on the 1880 US Census for Rockcastle County District 97 that her father and mother were born in New York. Other records probably exist, but I have not found them.  

The idea that Sarah's maiden name was Booth is from a register of marriages in Montgomery County, Virginia. On 27 Aug 1839 the register logs the bond^[M4] of William Lawrence and Sarah Booth with the actual marriage^[M5] taking place on 1 Sep 1839.^[S33] It is important to note that this William is not the son of Elder John Lawrence, but the son of John Lawrence, Jr. John Lawrence, Jr was the grandson of Elder John and nephew of the William (b. 1764) who moved to Rockcastle County, Kentucky. The William (b. abt 1815) who married Sarah Booth is the great grandson of Elder John and great nephew of the older William (b. 1764)! In addition, Sarah Booth was born in Floyd County, Virginia whereas the other Sarah was born in New York.  

 

The younger William and Sarah, who lived out their lives in Virginia, died about a month apart (5 Mar 1865 and 7 Feb 1865, respectively) of typhoid fever in Floyd County, Virginia.^[S1] By comparison, William (son of Elder John Lawrence and uncle of John Lawrence Jr) was 75 years old when the younger couple were married in 1839 and had been living in Rockcastle County, Kentucky for 27 years.  

There is a record of a William Lawrence marrying a Sally Shelton on 5 May 1785 in Pittsylvania County, Virginia. This may or may not be the same William (b. 1764) who is the son of Elder John Lawrence. I have found no records of the death or burial of the older William and Sarah who lived out their remaining years in Kentucky. 

While it is not impossible that two different women with the name of Sarah Booth married two men named William Lawrence, it does seem improbable.