Archaeological finds in the Turku area date back to the Stone Age, but the city was founded when Catholic settlement began at Koroinen, near the present centre of Turku, in 1229. The consecration of a new church in 1300 and the construction of Turun Linna (Turku Castle) created an administrative and spiritual base for rule.

The original Swedish name, Åbo, comes from a settlement (bo) on a river (å). The town was the second largest in Sweden, though much of it was levelled by fires, including the Great Fire of 1827. When the Russians took over, the city's long Swedish connection led them to make their new capital Helsinki, leaving Turku to concentrate on commerce. As such, the name Turku is an archaic Russian word for ‘marketplace’. Today Turku’s centre is still its kauppatori (market square), situated 3km northeast of the harbour.