Suleiman the Magnificent, the most powerful ruler in the world, was determined to conquer Europe. Only one thing stood in his way: a dot of an island in the Mediterranean called Malta, occupied by the Knights of St. John, the cream of the warriors of the Holy Roman Empire. A clash of civilizations the likes of which had not been seen since Persia invaded Greece was shaping up. Determined to capture Malta and use its port to launch operations against Europe, Suleiman sent an armada and an overwhelming army. A few thousand defenders in Fort St. Elmo fought to the last man, enduring cruel hardships. When they captured the fort, the Turks took no prisoners and mutilated the defenders' bodies. Grand Master La Vallette of the Knights reciprocated by decapitating his Turkish prisoners and using their heads to cannonade the enemy. Then the battle for Malta began in earnest: no quarter asked, none given.
Ernle Bradford's The Great Siege: Malta 1565. Bradford's story of Suleiman's siege and Valette makes a good long audio book, and you should find it somewhere for free. St John's is still an international Sovereign Order ("governs itself without interference" *) and the world's oldest surviving chivalric order. *HQ in Rome, "Defence of the (Catholic) faith and assistance to the poor".