Next to the dean (as a rule) is the precentor (primicerius, cantor, etc.), whose special duty is that of regulating the musical portion of the services. The precentor presides in the dean's absence, and occupies the corresponding stall on the north side, although there are exceptions to this rule, where, as at St Paul's, the archdeacon of the cathedral city ranks second and occupies what is usually the precentor's stall.