The sovereign monastic-military state of the Knights Hospitaller (Order of St John) on Rhodes and the surrounding Dodecanese, established after their 1306-1310 conquest of the island from the Byzantines — a Christian corsair and crusading power astride the sea lanes between the Aegean and the Levant through the 14th and 15th centuries, famously repelling a major Ottoman siege in 1480.
Fell to Sultan Suleiman the Magnificent after a six-month siege in 1522; the surviving Knights were permitted to withdraw, eventually relocating to Malta in 1530 (canonical's Hospitaller Malta, Q3355522, is the direct successor state).
The atlas holds 3 border frames for Hospitaller Rhodes — the shape you scrub through changes in 1310 · 1350 · 1426.
Polity-specific scholarly study of the Hospitaller state's rural administration on Rhodes during exactly this period, verified on Open Library (OL21301537W).