Tvrdalj is the sixteenth-century fortified house of the Croatian poet Petar Hektorović in Stari Grad, built between 1514 and 1569 partly as defence against Ottoman raids and partly as a private literary retreat. The walls form a square around an internal courtyard, and the centre of the courtyard is occupied by a rectangular saltwater fish pond fed directly from the bay.
The walls are inscribed with Latin and Croatian aphorisms of Hektorović's own composition — meditations on mortality, the fall of empires, and the consolation of fish. The walled garden behind, planted with pomegranates and figs, is a small piece of Renaissance horticulture. Entry is a few euros; allow half an hour.