Between 1530 and 1798, Malta was ruled by the Order of the Knights of St. John, also known as the Hospitallers. Granted the islands by Charles V of Spain, the Knights transformed Malta into a fortress state, pivotal in defending Europe from Ottoman expansion. Their most notable triumph came during the Great Siege of 1565, where they repelled a massive Ottoman invasion. Under their rule, Malta flourished as a cultural and architectural hub, with the construction of the fortified city of Valletta and many other impressive works. The Hospitaller period ended with Napoleon's invasion in 1798, marking a new chapter in Malta's history.