That the processional litanies take place on St Mark’s day is a mere accident, as is proved by the circumstance that in the oldest Latin Calendars—as, for example, in that of Fronteau, and in the Mainz edition of the _Gregorianum_—the _Litania major_ alone is put down on the 25th April without any mention of St Mark. (10) THE FEASTS OF ST PETER’S CHAIR (_18th January and 22nd February_) The historical investigation of these two feasts necessitates the consideration of two questions which must be discussed separately—first, their name and significance, and, secondly, the dates on which they are celebrated. _Cathedra_, when used in its literal sense by the oldest ecclesiastical writers, means the bishop’s seat in the apse of the church behind the altar, upon which he sat, when not otherwise engaged, during the performance of divine service. Figuratively, the _cathedra_ is the symbol of episcopal authority in general and of the bishop’s teaching authority in particular, just as the throne is the symbol of royal authority. _Cathedra Petri_, then, signifies especially the teaching authority of St Peter and his successors in the See of Rome, or, in other words, the Primacy. This can easily be proved from the writings of the Fathers, and the evidence for it has often been set forth in writings and treatises dealing specially with this question, and so it need not be repeated here.[645] That the feast was intended to celebrate the bestowal of the Primacy on St Peter is clear from the oldest liturgies, and will become sufficiently evident in the course of our remarks.[646]