Mary was mentioned in the 1765 will of her husband Isaac Gatewood. [Essex County, Virginia, Will Book 12, pages 225-226.]

In the name of God Amen, I Mary Gatewood being in a low State of health, though in perfect sense and sound memory, I do make this my last will & Testament, and making void all other heretofore made by me, First my Will and desire is that my land whereon I now live containing one hundred and twenty five acres be it the same more or less, may be sold after my death by my Executors hereafter mentioned, and the money arising from the sale of the said land be divided into four equal parts and to be disposed as followeth Viz. one fourth part to be divided equally between my Grand Children Wm. Fisher and Suckey Crittenden, and one fourth part between Isaac Hutchason and Sally Dunn my Daughter Tabatha’s Children, and one fourth part to my daughter Mary Kay, and one fourth part to my Daughter Jane Dunn. Item I give to my daughter Jane Dunn my Bell-mettle Skillet, my spice mortar & half a dozen china Plates; Item I give to my grand Son Wm. Fisher my large walnut Table and my Sorrel horse colt. Item I give unto my Grandson John Henshaw Gatewood one good cow, Item I give unto my daughter Jane my Trunk and all my wearing Cloths, also my will and desire is that all the rest of my estate shall be sold and equally divided amongst my Children to wit Andrew, Gatewood, Augustin, Richard, William, Sarah, Tabatha, Mary and Jane, or to their Representatives, Item my desire is that my two Grandsons, Robert Gatewood, & Thomas sons of Richard Gatewood, shall have three Sheep, I constitute and appoint Benjamin Fisher and William Fisher my executors In Witness whereof I have here unto set my hand and affixed my seal this twenty seventh day of June one thousand seven hundred and ninety eight.
Mary [X] Gatewood
Witnesses: William Salvator Jones, Susa Hill [sic], Ann [X] Cross
On 21 January 1799, presented in court by Benjamin & William Fisher and proved the oaths of William Salvator Jones, Susa Hall [sic], & Ann Cross. Certificate grant the said Benjamin and William Fisher in order to their obtaining probate.
[Essex County, Virginia, Will Book 15, page 436.]

On 21 January 1799, William Fisher and Benjamin Fisher were granted executorship of the estate of Mary Gatewood. William Fisher, Benjamin Fisher, and John Jones acknowledge their bond in the penalty of $2,000. [Essex County, Virginia, Will Book 15, page 436.]

Agreeable to an order of Essex Court dated the 21st day of January 1799 we the undersigned having met at the late dwelling House of Mary Gatewood decd. & proceeded to divide the negroes of Isaac Gatewood Decd. according to the last will and testament of the said decedent agreeable to the within statement given under our hands the 26th day of January 1799
Equal lots to Andrew Gatewood, Thomas Dunn, Augusten Gatewood, William Gatewood, John Kay, Richard Gatewood, Benj: Fisher, Charles Hutchason.
W Latane
James Upshaw jr.
Reuben Garnett
Sthreshly Rennolds
Returned on 18 February 1799 and ordered recorded.
[Essex County, Virginia, Will Book 15, pages 439–440.]

On 26 January 1799, an inventory and appraisal of the estate of Mary Gatewood deceased was made by William Hill, Thomas Hill, and Micajah Munday, and was returned and ordered to be recorded on 15 April 1799. [Essex County, Virginia, Will Book 15, pages 454–455.]