When he returned to Norway, Olav Engelbrektsson was briefly mentioned as a canon in Oslo but, by 10 May 1515, he was already in Nidaros ( now Trondheim ) as a canon.
 Seven months later, on 17 December 1515, he was promoted to the Dean of Nidaros, with a Papal dispensation from Pope Leo X to succeed the late Peter Jonsson Stut.
 Although he was only thirty years old at that time, Olav became the second most important member in the  Cathedral Chapter, next to the Archbishop of Nidaros, the Dane Erik Walkendorf.
 Walkendorf had been appointed to his post in 1510 by King Christian II of Denmark and Norway without any consultation or recommendations from the Cathedral Chapter.

Olav Engelbrektsson was responsible for the production of the sermons in the Nidaros Cathedral and probably sat on the editorial staff of the book for the Mass at the Cathedral, the Missale Nidrosiense [ Latin, Missal of Nidaros ], the first book printed in the Norwegian language.
Along with the cantor Peter Sigurdsson, Archbishop Walkendorf had the missal printed in Copenhagen in 1519.
 According to the church historian Oluf Kolsrud, it is "with his careful treatment of the Latin text, the excellent proof of Olav's learning" [ med sin omhyggelige behandling av den latinske tekstform et ypperlig bevis for Olavs lærdom ].
 A few years later, another book of liturgy was also published for Nidaros with the title of the Breviarium Nidrosiense [ Latin, "Breviary of Niadros" ].
 Olav was on good terms with Walkendorf and became his representative, i.e., the head of the ecclesiastical proceedings within the Archdiocese.
It also appears that he was also the Archbishop's economist and accountant.

When Walkendorf fled from the tyranny of King Christian II in 1521, the authority of the Archdiocese went to the Cathedral Chapter, whose chairman was Olav Engelbrektsson.
 Account books, the Register paa Sancta Oluffa Ioerdher ( a register of properties, ca.
1533 ) and extensive building activities suggests that Olaf was a "talented and versatile administrator" [ dyktig og allsidig administrator ] according to historian Øystein Rian.
Olav Engelbrektsson began the complete reconstruction of the Archbishop's Palace, whose hall in the north wing and parts of the west wing had been destroyed by the Danish troops in 1532.
When he returned to Norway, Olav Engelbrektsson was briefly mentioned as a canon in Oslo but, by 10 May 1515, he was already in Nidaros ( now Trondheim ) as a canon.  Seven months later, on 17 December 1515, he was promoted to the Dean of Nidaros, with a Papal dispensation from Pope Leo X to succeed the late Peter Jonsson Stut.  Although he was only thirty years old at that time, Olav became the second most important member in the  Cathedral Chapter, next to the Archbishop of Nidaros, the Dane Erik Walkendorf.  Walkendorf had been appointed to his post in 1510 by King Christian II of Denmark and Norway without any consultation or recommendations from the Cathedral Chapter.
Olav Engelbrektsson was responsible for the production of the sermons in the Nidaros Cathedral and probably sat on the editorial staff of the book for the Mass at the Cathedral, the Missale Nidrosiense [ Latin, Missal of Nidaros ], the first book printed in the Norwegian language. Along with the cantor Peter Sigurdsson, Archbishop Walkendorf had the missal printed in Copenhagen in 1519.  According to the church historian Oluf Kolsrud, it is "with his careful treatment of the Latin text, the excellent proof of Olav's learning" [ med sin omhyggelige behandling av den latinske tekstform et ypperlig bevis for Olavs lærdom ].  A few years later, another book of liturgy was also published for Nidaros with the title of the Breviarium Nidrosiense [ Latin, "Breviary of Niadros" ].  Olav was on good terms with Walkendorf and became his representative, i.e., the head of the ecclesiastical proceedings within the Archdiocese. It also appears that he was also the Archbishop's economist and accountant.
When Walkendorf fled from the tyranny of King Christian II in 1521, the authority of the Archdiocese went to the Cathedral Chapter, whose chairman was Olav Engelbrektsson.  Account books, the Register paa Sancta Oluffa Ioerdher ( a register of properties, ca. 1533 ) and extensive building activities suggests that Olaf was a "talented and versatile administrator" [ dyktig og allsidig administrator ] according to historian Øystein Rian. Olav Engelbrektsson began the complete reconstruction of the Archbishop's Palace, whose hall in the north wing and parts of the west wing had been destroyed by the Danish troops in 1532.
Olav Engelbrektsson