 Complete the following phrase:  Larger and smaller semantra have been used, the smaller being sounded first, followed by the larger, then by those of iron. Theodore Balsamon, in a treatise on the subject, compares the sounding of the little, great and iron semantra to the preaching of the Law and of the Gospel, and the Last Trumpet. He also says that the congregations were summoned by three semantra in monasteries, and only by one large one in parish churches. Moreover, he emphasises the persistence of the semantron in the East as a symbolic manifestation of difference with the Latin West it remains unclear if some isolated practices in the West such as the Basque txalaparta are associated with the pre-schism liturgy; in Byzantium, the use of bells did not really gather momentum until after the 