 Varniai cathedral school provided primary education.Giedraitis established and taught at educational courses in Alsėdžiai that prepared about twenty priests; one of them – – later became bishop of Samogitia.Based on the last will of his predecessor Jurgis Petkūnas, Giedraitis sponsored education of 12 clerics at the seminary in Vilnius laying the foundation for the Samogitian Priest Seminary.