She was the wife of Richard Rosewell and subsequently his widow. At the time of their marriage in 1681, Richard was 29 and Lydia was 15. Lydia was daughter of Lt. Thomas Trowbridge (1631-1702)–one of the original planters of New Haven Colony–and his wife Sarah (Rutherford) Trowbridge (1641-1687). She was also one of the few women who held a public position: she was appointed to collect the town rate unpaid for the year 1701. Apparently this job was left undone by the death of her husband. Lydia also owned land and was listed as a proprietor in the town plot in 1706.
In 1710, Col. Joseph Whiting asked permission for Lydia and himself to build a pew in the Meeting House. It was not granted.
Lydia is described in a history of the early colony as “the wealthy widow of John Alling’s predecessor as treasurer of the Collegiate School [Yale College], whose mansion occupied the northwest corner of Meadow and Water Streets.”