Conversion to the Episcopal Church of Berlin.
In 1930 the diocese of Berlin was founded and the church was converted to the Episcopal Church of Berlin and thus elevated to cathedral.
In the years 1930 to 1932 the church was rebuilt to fit the requirements of a bishop's see and cathedral by the architect Clemens Holzmeister.
The interior space of the cathedral was opened up behind the altar to become a small domed structure providing direct sight on the tabernacle.
The windows on the left and right of the altar became walled up to place cathedra (seat of the bishop) and organ propect.
The formerly painted ornaments became build in stucco. In the newly build cupola 12 pictures of evangelists and the fathers of the Church, painted by Peter Hecker, Cologne.