The founding of Turku, one of Finland’s oldest cities, is tied to the establishment of the region’s ecclesiastical and administrative centers in the 13th century. While the exact date of Turku’s founding is unclear, it likely developed in the 1280s or 1290s through a joint effort by the king, the bishop, and the Dominican Convent of Saint Olaf, established in 1249.
Before the city’s formal foundation, the area was already inhabited by farmers and possibly a peasant village. In 1229, Pope Gregory IX authorized the relocation of the episcopal seat from Nousiainen to nearby Koroinen, marking the growing importance of the region. Turku Cathedral, which became the seat of the Bishop of Turku, was consecrated in 1300. Though Turku never held official capital status, it became the most significant city in Finland during the Middle Ages, serving as the center of trade, shipping, and religious authority.
Turku also played a key legal role in Finland, hosting the country’s only lawspeakers and the Land Court of Turku, the highest court in the region from the 15th to 16th centuries. The city's early significance laid the groundwork for its lasting historical and cultural influence in Finland.