The local tradition says that during that journey, his body was placed on the ground and that a miraculous spring gushed from that spot and started to flow out of the mountainside just outside Strängnäs.

According to the source closest in time, a legend of the Danish king Saint Canute, which was authored about 1122 by Ælnoth of Canterbury, an Anglo-Saxon priest who had settled in Denmark, an "Eskillinus", an English bishop of noble origins, was killed by the "wild barbarians" (specified as the Suethi et Gothi, i.e. Swedes and Geats) among whom he was preaching the gospel.

[6] In its more developed form, the legend of Eskil is attested from the 13th century and known from a few different sources: according to this, he was successful in his mission during the reign of King Inge, but killed by Blot-Sweyn when trying to stop a pagan sacrifice on the hill where the Strängnäs Cathedral now stands.

Some Christians attempted to bring his body back to Fors, but got only so far as Tuna when a dense fog impeded their progress, which they took as a sign to bury the saint there.

This is confirmed, since the hill where the cathedral now stands is known to have been the ritual site and that the first wooden church built there was dedicated to Saint Eskil.

The monastery of Saint Eskil was completely destroyed by Swedish king Gustav Vasa during the Protestant Reformation and was replaced with the royal castle of Eskilstuna House.

A silver reliquary from the fifteenth century in the shape of a hand, to hold a piece of arm bone, is housed in the History Museum of Stockholm.