The main armoury of the Order of St John or The Palace Armoury at the Grandmaster's Palace in Valletta, Malta. Bronze cannons, as could be seen in the picture, were lighter than cast or wright iron, more powerful and accurate, and safer to use. But they were also three or four times more expensive than made from iron, therefore only wealthy rulers could afford them, and the Order of St John could it in the 16th—18th centuries because of revenue from corsairing activities in the Mediterranean Sea under its control.