Maiden name might not be Briggs. See article which discusses the matter. Since John Briggs identified himself as her brother during court hearings, Briggs seems a fair assumption to me.
In 1657, Dec. 10, Rebecca Cornell was granted 10 acres in lieu of 10 acres granted her husband. In 1659, she deeded these 10 acres to her son and daughter Kent. April 30, 1661 sold Thomas Hart for 30 Pounds two parcels of land containing 8 acres with house, fruit trees, etc.; confirmed by her son Thomas in 1663. October 25, 1663, conveys to her son Joshua 1/6th of a share of land at Coshena and Acookset (part of Dartmouth) in Plymouth Jurisdiction (This he conveyed on Nov. 21, 1664, to his brother Samuel along with 20 acres of land he bought from William Earle (brother of Sarah Earle?). July 27, she deeded to Thomas all her housing, orchard, land and fencing in Portsmouth, the 100 Pound bond to which she held at her death, eight years later. In 1669, she conveys to son Samuel land in Dartmouth, one-sixth of a share. (Footnote in Cornell's Genealogy of the Cornell Family: It appears Rebecca had three-sixths of a share; she conveyed to Samuel 1/6th, to Joshua 1/6th, perhaps 1/6th to John, who lived in Dartmouth. To Thomas she gave land in Portsmouth. Her other son, Richard, had gone to Long Island in 1656 and had probably received his patrimony).
On February 8, 1773, she died strangely in Portsmouth in her own dwelling house. On May 23, her son Thomas was charged with murder, tried and executed. See Thomas for more.
Witnesses in the trial were:
Her brother John Briggs
Mary, wife of John Cornell, her son
Thomas's sons: Thomas, Stephen, Edward & John
Her daughter, Rebecca Woolsey