[1] Descended from the noblest stock of Northumbria, as a young man he led the life of a soldier in the army of King Egfrid, the son of Oswy.
[2] When Eosterwine was twenty-four years old, he gave up the soldier's profession to become a monk in the monastery of Wearmouth, which was ruled by his cousin, Benedict Biscop.
[4] As superior "when he was compelled to reprove a fault, it was done with such tender sadness that the culprit felt himself incapable of any new offence which should bring a cloud over the benign brightness of that beloved face".
In the year 686 a deadly pestilence overspread the country; it attacked the community at Wearmouth and the youthful abbot was one of its victims.
Saint Benedict was absent in Rome at the time of his death and Sigfried was chosen by the monks as his successor.