to his time by archaeologists. Concerning the Hagia Sophia, which was constructed earlier, the procession was obviously within the church. It seems that the cherubikon was a prototype of the Western chant genre offertory. With this change came also the dramaturgy of the three doors in a choir screen before the bema (sanctuary). They were closed and opened during the ceremony. Outside Constantinople these choir or icon screens of marble were later replaced by iconostaseis. Antonin, a Russian monk and pilgrim of Novgorod, described the procession of choirs during Orthros and the divine liturgy, when he visited Constantinople in December 1200: When they sing Lauds at Hagia Sophia, they sing first in the narthex before the royal doors; then they enter to sing in the middle of the church; then the gates of Paradise are opened and they sing a third time before the altar. On Sundays and feastdays the Patriarch assists at Lauds and at the Liturgy; at this time he blesses the singers from gallery, and ceasing to sing, they proclaim the polychronia; then they begin to sing again as harmoniously and as sweetly as the angels, and they sing in this fashion until the Liturgy. After Lauds they put off their vestments and go out to receive the blessing of the Patriarch; then the preliminary lessons are read in the ambo; when these are over the Liturgy begins, and at the end of the service the chief priest recites the so-called prayer of the ambo within the sanctuary while the second priest recites in the church, beyond the ambo; when they have finished the prayer, both bless the people. Vespers are said in the same fashion, beginning at an early hour. Monastic reforms in Constantinople and Jerusalem By the end of the seventh century with the reform of 692, the kontakion, Romanos' genre was overshadowed by a certain monastic type of homiletic hymn, the canon and its prominent role it played within the cathedral rite of the Patriarchate of Jerusalem. Essentially, the canon, as it is known since 8th century, is a hymnodic complex composed of nine odes that were originally related, at least in content, to the nine Biblical canticles and to which they were related by means of corresponding poetic allusion or textual quotation (see the section about the biblical odes). Out of the custom of canticle recitation, monastic reformers at Constantinople, Jerusalem and Mount