Principality of Krk

The Principality of Krk was a semi-independent principality on the Croatian-Adriatic island of Krk that existed from 1451–1480 during the late middle ages. Previous to the principaly's foundation, Krk and the surrounding lands were ruled by several Frankopan princes. In 1451, Prince Ivan VII, who ruled parts of Krk, and parts of the nearby mainland, in a dispute with his brother, traded all his land on the mainland for his brother's land on the rest of the island, forming a Krk under the single ruler Ivan VII. During Ivan's reign (1451–1480) many religious structures and monuments were formed, improving the towns on the island greatly. The island's semi-independence came to an end when the Republic of Venice invaded in 1480, when they tricked Ivan VII into leaving the island.

Source: "The Island of Krk" by Denis Lešić