Creation of the royal duchy of Gandia Historical milestone · Gandia, La Safor, Valencia Image of Gandia, not of the place itself. In 1399 King Martin the Humane granted Alfons d'Aragó the Elder the title of duke of Gandia. His court attracted poets and jurists and promoted the founding of the monastery of Cotalba in 1388; in 1485 the duchy passed into the hands of the Borja family. 1399 Photo: 19Tarrestnom65 (CC BY-SA 4.0) What to see and do in Gandia