Parga Castle occupies a rocky height between the harbor and Valtos Bay on the coast of Epirus. Fortification developed there during the Middle Ages as local rulers, western powers, and the Ottoman Empire competed for the Ionian shore. Early works were repeatedly attacked or destroyed, and the visible complex reflects many rebuildings rather than one founding moment. The site protected a town whose people relied on maritime trade, fishing, farming, and connections with the Ionian islands while seeking a measure of autonomy from stronger neighboring states.

Venice established a durable relationship with Parga in the fifteenth century and ultimately incorporated it into its maritime system. Ottoman attacks and the raid of Hayreddin Barbarossa in 1537 caused severe destruction. Venetian authorities and residents rebuilt the defenses, adding walls, bastions, gates, magazines, cisterns, and houses. The winged lion of Saint Mark and later inscriptions marked the republic's authority. Supplies could reach the fortress from protected bays, allowing the community to endure threats from the landward side.

Venetian rule ended when France took the Ionian possessions in 1797. French, Russo-Ottoman, and again French administrations followed during the Napoleonic wars, each viewing Parga as a strategic coastal point. Britain assumed protection after Napoleon's defeat. These rapid changes intensified local fears of Ali Pasha of Ioannina, who had long sought the town. The fortifications were strengthened into the early nineteenth century, but diplomacy rather than siege determined their fate when Britain agreed to transfer Parga to Ottoman authority.

In 1819 most Christian residents chose to leave rather than live under Ali Pasha, relocating to the British-held Ionian islands after compensation arrangements that remained deeply controversial. Ali occupied the town and remodeled the castle, adding or strengthening walls, a polygonal bastion, baths, and residential spaces associated with his household. After his fall in 1822, direct Ottoman administration followed. Parga remained within the Ottoman Empire until the Balkan Wars brought it into the Kingdom of Greece in 1913.

The castle's interior is now largely ruinous, but walls, gates, bastions, cisterns, and scattered buildings preserve the Venetian and Ali Pasha phases. Vegetation, earthquakes, coastal weather, and modern use require continuing oversight. The monument is inseparable from the town below and from the memory of the 1819 exodus. Parga Castle illustrates how a small maritime community navigated between empires, relying on fortification, foreign protection, and collective negotiation. Its most consequential transfer occurred not through a final assault, but through an international agreement that displaced much of the population.