Mary and her sister Elizabeth Young Banks were mentioned in the 19 February 1792 will of her father Richard Banks. The will does not explicitly state that they were under age, but their mother, Elizabeth, was given the use of the whole estate to provide for herself and for them. If Elizabeth were to remarry, each child was to receive one third of the estate, and following her death one half. [Essex County, Virginia, Will Book 15, pages 11–12.]

On 22 January 1814, a division of the slaves belonging to the estate of Richard Banks, deceased, was made by Jno. Smith, Newman Brockenbrough, and W. Blake, to Elizabeth Banks, Polly Banks (also listed as Mary Banks), and Samuel Muse (who married Elizabeth Banks). On 29 January 1819, this was further acknowledged by Eliza S Banks and Wm L Waring. [Essex County, Virginia, Will Book 19, pages 31–32.]

Elizabeth Young Muse was mentioned in the 22 November 1821 will of her mother, Elizabeth Smith Banks, proved 16 December 1822. [Essex County, Virginia, Will Book 19, pages 351–352.]

On 26 December 1822, Samuel Muse and William L. Waring agreed that Joseph Janey, William Smith and Kemp Gatewood were to value and divide the remaining property of Richard Banks, deceased, as they were the only two devisees in right of their wives, Mary Waring and Elizabeth Y. Muse. The division was returned to court on 18 August 1823. [Essex County, Virginia, Will Book 19, pages 390–391.]

In 1832, orators and oratrices Elizabeth Y. Muse wife of Samuel Muse, and Mary Augusta, Lucy Ann, Catharine E. C., and Caroline L. Muse, and yr orator Richard J. Muse and Samuel W. Y. Muse the sd Sml W. Y., Mary Augusta, Lucy Ann, Catharine E. C. and Caroline infants under 21 by Richard J. Muse their next friend complained that on 19 November 1825 William B. Matthews conveyed to one Lawrence Muse a variety of property in trust for the support of your orators and oratrices and the said Samuel Muse. In 1832 Lawrence Muse died, and no one has been authorized to oversee the said Samuel Muse in the management and disposition of the property. [Essex County, Virginia, Box Chancery No. 43, item 43-A-10.]