Pillage of Sigtuna

The Pillage of Sigtuna was an event in the summer of 1187 described in the Eric Chronicles and in annals from the 14th century. According to the chronicle as quoted below, the town of Sigtuna was burnt by Karelians on August 12. Archbishop Johannes of Uppsala was killed near the Almarestäkets fort. At that time, Sigtuna was the most important town of medieval Sweden. The Eric Chronicles describes the events as follows:

Sweden then suffered serious harm,
From the Estonians, causing great alarm.
They sailed into Lake Mälar from the sea,
Whether calm or stormy it might be,
Secretly within the Svealand isles
In stealthily advancing files.
Once their minds to the idea did turn,
That they the town of Sigtuna should burn,
And so thoroughly they put it to the flame,
That it since then has never been the same.
There Archbishop Jon was killed,
A deed that many a heathen thrilled.[1]

According to the Eric Chronicles, Jon Jarl was also killed during the incident. The chronicle also describes that these events eventually led to the founding of Stockholm by Birger Jarl, who wanted to protect Sweden from sea invasions.[1]