Tvrdalj Castle (Croatian: Gradina Tvrdalj) is a castle in Stari Grad, on the island of Hvar, Croatia.
Tvrdalj was the summer residence of Petar Hektorović, the Croatian poet (1487–1572). During the 16th century, the island of Hvar came under attack from the Ottoman Turks. Hektorović, one of the local nobles, undertook to fortify his house so that it could act as shelter for the local citizens.
Tvrdalj is a well-preserved Renaissance building, with a long closed facade on the seaward side, to protect it from attack. The interior courtyard contains a sea-water fish pool, enclosed by a vaulted and arcaded terrace. Next to it is a tower with a dovecote. The living quarters, together with the servant quarters, and several wells, are arranged around the pool. Behind the main buildings is a walled garden where Hektorović cultivated herbs and medicinal plants.
A series of inscriptions are set into walls of the mansion in Latin and Croatian. Those in Croatian are considered to be some of the oldest extant.
PETRVS HECTOREVS MARINI FILIVS
PROPRIO SVMPTV ET INDVSTRIA
AD SVVM ET AMICOR, VSVM CONSTRVXIT
Translation: Petar Hektorović, son of Marin, built this at his own expense and by his own efforts, for his own and his friends' use.