The First period of French rule in the Ionian Islands (Greek: Πρώτη Γαλλοκρατία των Επτανήσων) lasted from June 1797 to March 1799. Following the fall of the Republic of Venice in May 1797, the Ionian Islands, a Venetian possession, were occupied by Revolutionary France. The French instituted a new, democratic regime and, following the Treaty of Campo Formio, annexed the islands to France, forming the three departments of Corcyre (Corfu), Ithaque (Ithaca) and Mer-Égée (Aegean Sea).
Originally widely welcomed, French rule began to grow oppressive to the islanders, and aroused the enmity of the Ottoman and Russian Empires. In 1798, a joint Russo-Ottoman campaign was launched against the islands, culminating in the four-month siege of Corfu. Its fall in March 1799 signalled the end of French rule, and the islands were reorganized as the Russo-Ottoman protectorate of the Septinsular Republic. The islands were again annexed to France in 1807 after the Treaty of Tilsit, but retained many of the institutions of the Septinsular Republic. The French were evicted from most of the islands by the British in 1809–10; only Corfu resisted until 1814. In 1815, the British established the United States of the Ionian Islands.