In 1120 or 1121 (the exact date is unknown), the Portsoken was granted as a liberty to the Priory of Holy Trinity, which had been founded in 1107 by Queen Matilda, the wife of King Henry I. The sitting prior of Holy Trinity became, "ex officio", an alderman of the City of London Corporation representing the Portsoken ward, and remained so until the Dissolution of the Monasteries by King Henry VIII in 1531. The Ward originally extended as far south as the Thames, but the growth of the Tower of London beyond the line of the London Wall, disputes with the Tower, the creation of the Liberties of the Tower of London and other factors resulted in the southern area being lost to the ward and to the City of London as a whole, after around 1200.