Cathedral of Saint Bartholomew in Kapitul

In antiquity, a Roman bridge used to stand on the location of a modern railway bridge. Next to it, on the location of the later medieval capitol, was a Roman fort controlling the river passage.[4]

The foundation of the Diocese of Knin, according to Thomas the Archdeacon, can be traced back to the 11th century. The kings of Croatia, demanding to have their bishop, enthroned one in the Church of Holy Mary in modern-day Biskupija, Knin. The diocese was called the Croatian Diocese, and its bishop resided in the king's court and accompanied the royal entourage.[3] The existing section of the church was then extended to fulfill the needs of the bishop, while the building was renovated during the rule of Zvonimir of Croatia, who also donated the estate of Kosovo to the diocese.[5]

A 10th century Croatian interlace ornament from the Benedictine monastery of St. Bartholomew, containing the names of kings Stephen Držislav and Svetoslav Suronja.

Existing around the same time was a royal Benedictine monastery (monasterium regale) dedicated to Saint Bartholomew in Kapitul, whose abbots were also in the entourage of the Croatian rulers. Judging by the archaeological findings from that location, the complex can be traced back to the 10th century, at the latest.[3] Its excavated remains are conserved at the Museum of Croatian Archaeological Monuments in Split. These remains include tablets containing the names of two Croatian kings: Stjepan Držislav, and his successor Svetoslav Suronja, titled as dux Chroatorum on the inscription.

After the native kings of Croatia died out, the estate, along with the church, was donated by king Géza II of Hungary to the Diocese of Split, as claimed in one late 12th-century document.[5]

In 1203, Dobroslav, provost of Knin, initiated the construction of a new cathedral on the site of the previous royal monastery.[1] The church was dedicated to Saint Bartholomew in the 1380s, during the time of bishop Nicolas of Knin. The cathedral was described as "magnificent" upon its consecration.[3] At the same time, Saint Bartholomew also became the patron of Knin's cathedral chapter, and his image appeared on the chapter's seal.[6] The main apse of this new cathedral became a place of authentication (locus credibilis), and also most likely contained the chapter's archives. Along the main basilica was a church tower and the bishop's quarter with a backyard. The 16th century Francisian chronicler Ivan Tomašić in his Short Chronicle of Croatian Kingdom (lat. Chronicon breve Regni Croatiae) also claimed that the remains of Croatian king Demetrius Zvonimir were buried here, before the high altar.[5] [7]

After suffering some damage, the cathedral was reconstructed around 1360.

The Knin cathedral complex as it appeared on a 16th century Venetian map by Matteo Pagano.

Due to the permanent threat of Ottoman invasions and the aftermath of the Battle of Krbava Field, the seat of the diocese was relocated to the town of Cazin.[5] For the same reason, fortifications were erected around the cathedral complex by 1504. Somewhere in this time period, the diocese of Knin practically ceased to exist, remaining only as a formal title.[5]

In 1885, Austria-Hungary built the Knin-Siverić railway line across the location of the old medieval monastery. Croatian archaeological pioneer Lujo Marun made an arrangement with construction workers to hand over "anything they find underground, that might seem interesting." The 10th century stone tablet containing the names of Svetoslav Suronja and Stephen Držislav were discovered around this time.[1]

The cathedral remains in the 1920s, before its destruction by the Italians during World War II.

In the last 500 years, the site of the medieval cathedral was left devastated. During World War II, Fascist Italian troops completely destroyed the cathedral's remnants to build a barracks, after which the site was then settled by Romani people. The land then became an illegal dumping site after the Croatian War of Independence in the 1990s.[1] Although it was believed for 70 years that the cathedral was irretrievably lost, archaeologists from Split managed to recover its remains in September 2017.[8] Thus far, only the cathedral's northern wall and its frontage have been researched.[8]