The legend of Mykil steen in Sigtuna

Nyckelstenen, a flyttblock at Mälarens strand, approximately half a mile from Sigtuna, is mentioned in several sagas related to the sacking of Sigtuna in 1187. Among these tales, one suggests that the key to Mariakyrkans portar was dropped nearby during the raid. Another saga claims the keys to the city gates were placed in a hollowed log at the boulder and floated with the current to the site that became Stockholm.

Martin Aschaneus mentioned a cape called Sigtuna Nykell in 1612, noting it as the base of the tower that appeared in the levan. At that time, the legends were not yet widespread. The stone was depicted in Suecia Antiqua et Hodierna based on a drawing from 1695, where it was described as notable for the remarkable form nature had given it. It was depicted again in Georg Wallins Sigtuna stans et cadens (1729-32), which briefly mentions the stone and its painted keys, though it says nothing of the legends.

Johan Fischerström wrote in Beskrifning om Mälaren in 1785 that the impression suggests the keys were carved out. By then, the painted keys had faded and were no longer visible. The legend of the stone as the place where the key to Mariakyrkans portar was lost was first described in A.H. Wistrand's Sigtuna det forna och det nuvarande in 1847. By that time, the stone’s location had long been forgotten.

The stone was ‘rediscovered’ in 1966 by Jan Peder Lamm, who had last repainted it in 1922 or 1923. Lamm assumed that the stone, which originally marked the channel leading to Sigtuna and was called ‘Mykil steen’ (the great stone), was later corrupted to nyckelstenen and eventually gave rise to the legend.

Sources: https://suecia.kb.se/F/?func=find-c&ccl_term=wso+%3D+asaml&local_base=sah

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons