Diet of Porvoo

The Diet of Porvoo (Finnish Porvoon maapäivät, or unhistorically Porvoon valtiopäivät; Swedish Borgå landtdag), was the summoned legislative assembly to establish the Grand Principality of Finland in 1809 and the heir of the powers of the Swedish Riksdag of the Estates. The session of the Diet lasted from January to July 1809.