In his 1751 will, Cornelius O'Bryan named his wife as Rebecca, bequeathing her 100 acres as long as she remained his widow and appointing her as one of his executors. There is no record proving when or where Rebecca was born or who her parents were. To the contrary, the earliest surviving record of Cornelius indicates otherwise ...
The first record we have of Cornelius is a land patent dated 9 July 1724 in which he and six others were impressed into the service of James Christian as part of a patent for 400 acres on the north side of the James River, "beg. at cor. of EDWARD BAYS & MR. TARLTON WOODSON, to W. side of Little Cr. [Creek?]", somewhere in Virginia. [Source: Foley, Louise Pledge : Early Virginia Families Along the James River (1974), p. 62] Since Cornelius came to Virginia from Ireland as an indentured servant, it is not reasonable to believe that he married a woman who was born in Massachusetts and whose parents never left the State of Massachusetts.
While Cornelius's will names his wife as Rebecca, it does not mention the surname Green. There is, in fact, no source offered that proves Rebecca's maiden name. Green was merely suggested by family trees at Ancestry.com, which neither requires nor verifies sources for anything its users claim.