The ship went through several changes in her armament throughout her career, most significantly accompanying her "rebuilding" in 1536 (see below), when the number of anti-personnel guns was reduced and a second tier of carriage-mounted long guns fitted. There are three inventories that list her guns, dating to 1514, 1540 and 1546. Together with records from the armoury at the Tower of London, these show how the configuration of guns changed as gun-making technology evolved and new classifications were invented. In 1514, the armament consisted mostly of anti-personnel guns like the larger breech-loading iron "murderers" and the small "serpentines", "demi-slings" and stone guns. Only a handful of guns in the first inventory were powerful enough to hole enemy ships, and most would have been supported by the ship's structure rather than resting on carriages. The inventories of both the "Mary Rose" and the Tower had changed radically by 1540. There were now the new cast bronze "cannons", "demi-cannons", "culverins" and "sakers" and the wrought iron "port pieces" (a name that indicated they fired through ports), all of which required carriages, had longer range and were capable of doing serious damage to other ships. The analysis of the 1514 inventory combined with hints of structural changes in the ship both indicate that the gunports on the main deck were indeed a later addition.