Within the walled town the most interesting building is the knights' old hospital, centred on a courtyard bounded by two storeys of arcaded galleries, with simple vaulting below and a flat wooden roof above. Along the east side runs a magnificent Gothic hall with central columns and little chambers let into the walls. This was the main ward of the hospital and the chambers were for isolating infectious cases.

Rhodes was attacked by the Ottomans in 1440, 1444, 1469 and 1480. It required a six-month siege by 400 ships and around 200,000 soldiers under Suleiman the Magnificent to force its inevitable surrender on Christmas Eve, 1522. 

The evacuation of Bodrum and Kos followed soon after and the knights became peripatetic till the Emperor Charles V gave them Malta in 1530. That would prove their final line of defence against Ottoman Muslim forces. Malta was tested to the utmost — and not found wanting — in the Great Siege of 1565.