In 1453 the Muslims finally captured Constantinople and became the major force in the Eastern Mediterranean. In the West was the Christian Spanish King Charles V who was also the Emperor of the Holy Roman Empire. However they were not the only forces to be dealt with. In  the East the Muslims had continuous wars with the Persians and other Muslim leaders in various lands. The the West Christian France was a force that was always trying to create problems for the Spanish. When Charles retook Tunis on one of his campaigns the Spanish were shocked to see French cannonballs being used by the Muslims. And when the Muslims decided to try and take parts of Italy they forged a treaty with France to split the country, even though they were never able to complete their conquest.

(Book – Empires of the Sea: The siege of Malta, the battle of Lepanto, and the contest for the center of the world – Roger Crowley)