Chronicle, December 3
On this day, December 3, 1257, a treaty was signed between Kotor and Dubrovnik on peace and friendship between the two cities, and that merchants from one could operate freely in the other city, without paying customs and duties, except for those normally paid by domestic merchants.
Kotor reached the peak of its autonomy in the Nemanjić state. In the Middle Ages, the Kotor municipality included the Vrmac peninsula and Dobrota do Ljuta, and also included Perast and Prevlaka with the Luštica peninsula. In the Middle Ages, Tivat was a summer resort for the Kotor nobles. The Lower Adriatic and Zeta prospered economically and culturally under the Nemanjić rule. News from that time about the people of Zahumlje and their seafaring undoubtedly partly refers to the people of Pelješac.
At that time, Kotor was the main port and the first trading city in Serbia. It was known as the “king’s court” and also as the “table and glorious” city, as Emperor Dušan called it. Nemanja fortified Kotor and had a court there. His son Vukan lived there. Stevan the First-Crowned visited Kotor, as did Nemanja’s youngest son Rastko – Saint Sava, when he founded the Zeta episcopate on Prevlaka near Tivat. Queen Jelena of Anjou, mother of Dragutin and Milutin, was particularly fond of Kotor and through her many Kotor residents rose to high positions at the Nemanjić court. King Dragutin visited Kotor, as did King Milutin several times. Stevan Dečani entrusted the Kotor Franciscan, Fra Viti, with the construction of his endowment of Visoki Dečani. Dušan entrusted the state function to Nikola Buća, and then to Pavle Paskvalić, and his son Uroš had two ministers of finance (protovestijar). The Nemanjićs did not interfere at all with the autonomy of the city and its communal organization. Kotor preserved its city administration, the prince, the Great and Small Councils, its statute, mint and its money. Maritime trade received an even stronger stimulus under the Nemanjićs. During the Nemanjić era, Kotor had its own shipbuilders, shipyards and ships. However, data on these ships are scarce and are only mentioned in a few documents. The shipyard in Perast is also mentioned. There is much more data on maritime trade transactions, the purchase and sale of ships, and shipbuilding. After the death of the last Nemanjić, the central government in Serbia weakened and with the collapse of the Serbian state, the independence of the coastal regions began. Kotor and Boka were temporarily under the protection of Hungary, and then of King Tvrtko. There is information that there was a shipyard on Prevlaka where both merchant and warships were built and repaired. In the literature on Boka maritime affairs, Kotor is mostly associated with Emperor Dušan, but there is information that the shipyard on Prevlaka was also used by Emperor Dušan's war fleet, especially his new ships purchased in Venice. There, the ships from Emperor Dušan's fleet were further armed and prepared for combined infantry and navy combat. There is information that for some time part of Emperor Dušan's fleet was anchored on Prevlaka.
It should be borne in mind that the term “arming ships” once also meant supplying ships with crews. Dančulovina on the hills to Prevlaka is a medieval castle, the age of which has not been determined, but it is assumed to be as old as the monastery on Prevlaka near Tivat. Legend has it that Emperor Dušan stayed in this castle and that in memory of that stay, an effigy of him was made, which was in the Dančulovina castle until the beginning of the First World War, when it was removed by the Austro-Hungarian gendarmes. During his visit to Prevlaka, Emperor Dušan lavishly gifted the monastery and praised the monks for cultivating friendship with the people of Dubrovnik.

https://svetigora.com/ljetopis-3-decembar-2019/