Chatham has had an association with the Royal Navy since Elizabethan times, moving to its current site in 1622. It provided the facilities to build, repair, maintain and supply ships. In the mid-nineteenth century, work began on expanding the dockyard into St Mary's Island, where three huge basins and five new docks were constructed, almost quadrupling its size, in order to support twentieth-century vessels. Work then commenced on a new home for Royal Navy seamen.