The Venerable Order of Saint John exists to this day across the UK and America, a charitable institution with 25,000 official members and twice as many volunteers, tracing its membership to the era of the Crusades. The monastic order began by caring for Jerusalem pilgrims, then by providing them with armed escort. It then grew into a substantial force of its own, raiding Turkish merchant ships from their fortified island redoubt. But a new force was rising in the region, the Ottoman Emperor Mahomet II who, having dispensed with Constantinople – that other Christian fortress – turned his attention to the Knights of Rhodes.

On this day, December 20, 1522, after a six month siege, the defenders and citizens of Rhodes negotiated a surrender with the Ottomans. They would be granted safety if they left the island.

The siege took a heavy toll on both sides – the Ottomans took casualties assaulting the bulwarks of Rhodes, while the Knights were low on supplies. On multiple occasions, Turkish forces breached the outer defenses, only to be thrown back. Mahomet still had the upper hand, but in the interest of speeding up the inevitable, he offered the defenders an opportunity to depart in peace. This was to be his undoing: four decades later, the Ottoman siege of Malta, where the Knights of Rhodes fled, was thrown back, possibly saving Europe from domination.