The story
The area of Porvoo has been inhabited since the Stone Age. In prehistoric times, the river Porvoonjoki was a route of commerce for Finnish tribal Tavastians who primarily inhabited the inland regions. The Tavastians also had some permanent settlements in the area, such as the village of Hattula (later Strömsberg), which was named after an inland Tavastian village. The original name of the river Porvoonjoki was possibly Kukinjoki. The name derives from the name of the trade vessel cog which was a common merchant ship in the Baltic Sea in medieval times. The early center of the area was Saksala, meaning "the place of the Germans", and deriving from the merchants who were trading in Saksala.
Porvoo was colonised by Swedes in the 13th and 14th centuries after the so-called Second Crusade against Tavastians in 1249–1250. The colonisation was led by the Catholic Church and the kingdom of Sweden. The colonists originated from Svealand, and were provided with seeds, cattle and, tax exemption for four years.
The oldest known written mentions of Porvoo are from the early 14th century. In circa 1380, Porvoo became the third town in Finland to be granted official town rights, after Turku in 1229 and Ulvila in 1365. However, it is also claimed to have been founded as early as 1347, which would make it the second oldest after Turku. Due to land rise and loss of shipping access, Ulvila lost town rights to nearby Pori in 1558.
When Sweden lost the city of Vyborg to Russia in 1721, the episcopal see was moved to Porvoo in 1723. At this time, Porvoo was the second largest city in Finland.
In 1760, roughly two-thirds of all buildings in Porvoo burned to the ground in a conflagration. During rebuilding, the city planning wasn't altered, instead new buildings were built upon the existing medieval foundations.
After the conquest of Finland by Russian armies in 1808, Sweden had to cede Finland to Russia in 1809 (the Treaty of Fredrikshamn). The Diet of Porvoo in 1809 was a landmark in the History of Finland as tsar Alexander I made Finland an autonomous Grand Duchy. In 1923, six years after Finland's independence, the former Diocese of Vyborg, which operated in Porvoo, was replaced by a current Swedish-speaking diocese of the Evangelical Lutheran Church of Finland, the Diocese of Porvoo.
The Porvoo Common Statement is a report issued at the conclusion of theological conversations by official representatives of four Anglican churches and eight Nordic and Baltic Lutheran churches in 1989–1992. It established the Porvoo Communion, so named after the Porvoo Cathedral where the Eucharist was celebrated on the final Sunday of the conversations leading to the Statement.
The old city of Porvoo was formally disestablished and the new city of Porvoo founded in 1997, when the city of Porvoo and the rural municipality of Porvoo were consolidated.
From Wikipedia’s article on Porvoo, shared under CC BY-SA 4.0.5

