Phillis was enslaved, in succession, by Dr. Joseph Sayer, his daughter Eunice Sayer Gilman, and by her sister Elizabeth Gilman.

In his will dated July 12, 1766, Dr. Sayer wrote "to my daughter Eunice ... my Negro girl Philis." According to the abstract, the probate proceeding occurred on April 11, 1774. - Frost, Vol. I, p. 713

"Dr. Sawyer who died in 1774, says in his will, 'I give to my daughter Eunice, one-third part of the schooner Prosperous, also my negro girl Phillis.' Previously he owned two others, Scipio and Sharper." - Bourne, p. 408

In the abstract of the 1775 probate proceeding, it's stated that Eunice Gilman left "to my sister Elizabeth Gilman my Negro girl Phillis & if he be living to my son Ebenezer when he comes of age & if not, then to said sister." - Frost, Vol. II, p. 730

Bibliography:

The History of Wells and Kennebunk from the Earliest Settlement to the Year 1820 - by Edward Bourne (1875)

Maine Probate Abstracts Vol I 1687-1775 - John Eldridge Frost (1991)