[1] Occupying the see of Patras since 3 January 1317,[2] he proved an able and energetic prelate, and during his tenure he acted as a virtually autonomous lord.
Aside from adjudicating differences between the various feudal lords, his main responsibility during those years was the provisioning of the Achaean fortresses with grain, which had to be imported from Italy.
[10] Consequently, when Frangipani died in 1337, Bertrand laid siege to Patras hoping to reduce it to obedience before the arrival of his successor, Roger.
Pope Benedict XII reacted by declaring the city "land of the Holy Roman Church" and placed the Principality under the interdict.
As a result, Bertrand had to retreat, and the Archbishop became independent, although his secular fiefs still owed allegiance and services to the Prince.