He was converted to the faith by Saint Anscharius, and for his zeal in propagating the same, and because in the time of a great famine he could not be compelled to offer sacrifice to the idols of Upsal, was sacrificed to them by the rebellious inhabitants of Birca, at that time the usual residence of the kings of Sweden. From the ruins of Birca, Stockholm took its rise, though built at a considerable distance from it.
- Father Alban Butler. “Saint Olaus, King of Sweden, Martyr”. , 1866. CatholicSaints.Info. 3 July 2014. Web. 6 May 2016. <>