Portsmouth was crucial to the defence of Tudor England and consequently it was mapped for military planning purposes throughout the Tudor period from 1545. The resulting sequence of maps records much of the town and harbour. The maps offer opportunities for furthering our understanding of Tudor Portsmouth and its population Additionally, images of the urban landscape provided by the “Cowdray Engraving”, which depicts the loss of Henry VIII’s warship Mary Rose on the 19th July 1545, may also be considered and compared with those presented in the early maps of the town. This paper considers the Portsmouth maps of 1545, 1552, 1584 and the chart of Portsmouth Harbour dating from between 1586 and 1620. These are examined in relation to one another and compared with evidence from the Cowdray Engraving.