Even though its area has been settled since prehistoric times, the most important part of Dubrovnik's history begins in the 7th century. In its beginnings, it was under Byzantine and Venetian authority, but over time it develops a certain degree of autonomy. Developed diplomacy and taking advantage of historical circumstances lead to the founding of the Republic of Ragusa in the 14th century. Republic grew to be a regional force, and it excelled in its knowledge of trade, sailing, and diplomacy. The slave trade was forbidden in the Republic of Ragusa in 1416, and it was the first abolishment of the slave trade in the human history. The Republic of Ragusa was also the first republic in the world to officially recognize the United States of America. Even though it managed to hold onto its independence in the worst years in Croatian history, Republic was abolished in 1808. by the forces of Napoleon, and after their departure it became permanently connected with Croatian lands. After World War II it's a part of Croatian state in Yugoslavia, and since 1991. it's an integral part of the Republic of Croatia.