Built between the 14C and 16C, this grey-granite cathedral with decorated red-brick gables and a shingled roof often suffered damage. On 29 March 1809, the date of the creation of the autonomous Grand-Duchy, is also an important date for the cathedral as it was on this day that Russian Tsar Alexander I solemnly swore to respect the Finnish laws of religion. Visitors will see a statue of the tsar (1909) and a copy of his oath. The paintings of the apostles date from the 18C, as do the badges on the walls.