Other noteworthy presences in terms of religious establishments refer to the Church of San Martino, to San Ferdiano (Via San Lorenzo, Pisa, Italy), San Sisto and to Santo Stefano di Cavalieri, as well as to San Cristina and San Paolo all Orto. This plethora of churches is the direct result of the fact that the city used to have a leading role as far as Christianity and its history are concerned, Pisa having been, for a long time, an ecclesiastical city since the beginning of the 4th century, when it hosted a bishopric.