source is the Tipografsky Ustav written about 1100. Its gestic notation was different from Middle Byzantine notation used in Italian and Athonite Kontakaria of the 13th century, where the gestic signs (cheironomiai) became integrated as "great signs". During the period of psaltic art (14th and 15th centuries), the interest of kalophonic elaboration was focussed on one particular kontakion which was still celebrated: the Akathist hymn. An exception was John Kladas who contributed also with kalophonic settings of other kontakia of the repertoire. Some of them had a clear liturgical assignation, others not, so that they can only be understood from the background of the later book of ceremonies. Some of Romanos creations can be even regarded as political propaganda in connection with the new and very fast reconstruction of the famous Hagia Sophia by Isidore of Miletus and Anthemius of Tralles. A quarter of Constantinople had been burnt down during a civil war. Justinian had ordered a massacre at the hippodrome, because his imperial antagonists who were affiliated to the former dynasty, had been organised as a chariot team. Thus, he had place for the creation of a huge park with a new cathedral in it, which was larger than any church built before as Hagia Sophia. He needed a kind of mass propaganda to justify the imperial violence against the public. In the kontakion "On earthquakes and conflagration" (H. 54), Romanos interpreted the Nika riot as a divine punishment, which followed in 532 earlier ones including earthquakes (526–529) and a famine (530): According to Johannes Koder the kontakion was celebrated the first time during Lenten period in 537, about ten months before the official inauguration of the new built Hagia Sophia on 27 December. Changes in architecture and liturgy, and the introduction of the cherubikon During the second half of the sixth century, there was a change in Byzantine sacred architecture, because the altar used for the preparation of the eucharist had been removed from the bema. It was placed in a separated room called "prothesis" (πρόθεσις). The separation of the prothesis where the bread was consecrated during a separated service called proskomide, required a procession of the gifts at the beginning of the second eucharist part of the divine liturgy. The troparion "Οἱ τὰ χερουβεὶμ", which was sung during the procession, was often ascribed to Emperor Justin II, but the changes in sacred architecture were definitely traced back