Burgess, Mathis or Mathers family

I found online, a widows penson request by Margaret Burgess, widow of William Burgess, who died from disease Sept 1814 during the war of 1812.

It states that Margarets maiden name was Mathis and shows relatives attesting to her request as R.W. Mathis and Sintha Mathis (Mathers) of Loudoun County, Va in the town of Aldie. Also in her family was Lousia Mathis Burgess who owned land in Broad Run.

It's now a puzzle as when Margaret became a widow in 1814, it shows children born William H. Burgess between 1812-1814, and Roxann(e)a about 1820-22, and John possibly later.

Would like to know who Margarets parets are as well as the history of this family. Thanks in advance.