Fortress of Klis

The Klis Fortress (Croatian: Tvrđava Klis; Italian: Fortezza di Clissa) is a medieval fortress situated above the village of Klis, near Split, Croatia. From its origin as a small stronghold built by the ancient Illyrian tribe Dalmatae, to a role as royal castle and seat of many Croatian kings, to its final development as a large fortress during the Ottoman wars in Europe, Klis Fortress has guarded the frontier, being lost and re-conquered several times throughout its two-thousand-year-long history. Due to its location on a pass that separates the mountains Mosor and Kozjak, the fortress served as a major source of defense in Dalmatia, especially against the Ottoman Empire. It has been a crossroad between the Mediterranean Sea and the Balkans.

Since Duke Mislav of the Duchy of Croatia made Klis Fortress the seat of his throne in the middle of the 9th century, the fortress served as the seat of many Croatia's rulers. His successor, Duke Trpimir I, is significant for spreading Christianity in the Duchy of Croatia. He expanded the Klis Fortress, and in Rižinice, in the valley under the fortress, he built a church and the first Benedictine monastery in Croatia. During the reign of the first Croatian king, Tomislav, Klis and Biograd na Moru were his chief residences.

In March 1242 at Klis Fortress, Tatars serving in the Mongol army suffered a major defeat while in pursuit of the Hungarian army led by King Béla IV. During the Late Middle Ages, the fortress was governed by Croatian nobility, amongst whom Paul I Šubić of Bribir was the most significant. During his reign, the House of Šubić controlled most of modern-day Croatia and Bosnia. Excluding the brief possession by the forces of Bosnian King, Tvrtko I, the fortress remained in Hungaro-Croatian hands for the next several hundred years, until the 16th century.

Klis Fortress is best known for its role in the Ottoman invasion of Europe in the early 16th century. Croatian captain Petar Kružić led the defense of the fortress against a Turkish invasion and siege that lasted for more than two and a half decades. During this defense, as Kružić and his soldiers fought without allies against the Turks, the military faction of Uskoks was formed, which later became famous as an elite Croatian militant sect. Ultimately, the defenders were defeated and the fortress was taken by the Ottomans in 1537. After more than a century under Ottoman rule, in 1669, Klis Fortress was besieged and seized by the Republic of Venice. The Venetians restored and enlarged the fortress. In 1797, the fortress was taken by Austria after the Fall of the Republic of Venice. Today, Klis Fortress contains a museum where visitors to this historic military structure can see an array of arms, armor, and traditional uniforms.