Forceful and determined, he summoned the bishops of the Holy Roman Empire to attend an assembly at Mainz on 8 September 1122. He expected absolute obedience, so much so that it took the mediation of Archbishop Adalbert of Mainz to prevent the suspension of Saint Otto of Bamberg for non-attendance. The struggle came to a conclusion with the Concordat of Worms in 1122 and the ""Pactum Calixtinum"" that was almost entirely due to Lamberto's efforts was effected on 23 September 1123.