the marriage in early ages was prevailing in europe itself, especially the early marriage of kings and rulers in the twelfth century for the purpose of creating alliances guaranteeing the continuity of peace. an example for that is the child empress "anias", in france, the wife of two byzantine emperors: emperor alexios kamanos ii, and the emperor andronikos kamanos i, respectively.
according to (william of tyre), anias was just eight years old when she reached constantine while alexios was thirteen years old (2). moreover, the wife of alexios kamanos i was twelve years old when she married and became an empress before attaining fifteen years. as for the empress of byzantium "theodora" the wife of manwel, she was thirteen years old when she married the prince of jerusalem "baldwin iii"; moreover, "margret maria hingaria" married "izak anglos ii" when she was nine years.
the age of ainas in such era was not something extraordinary. it was even a traditional matter that the new bride and bridegroom meet in constantine, in the house of the spouse who has the higher social rank (3). however, before alexios completed the third year as an emperor, the cousin of his father andronikos has appointed himself as an associate emperor (born in 1118, i.e. he was sixty five years old) and then overthrew alexios by force and married "aainas" although there were about fifty years gap between them (4).
this clearly demonstrates that the marriage of young girls to men over sixty years old was something usual in europe among the governing class itself; so, what about the public then? of course such kind of marriage was prevailing among the public in europe itself after more than five centuries from the marriage of muhammad – peace be upon him – and aisha.
 william of tyre, history of the deeds done beyond the sea, 13.4; p. wirth, 'wann wurde kaiser alexios ii. geboren?' byzantinische zeitschrift, 49 (1956), 65-7.
 one example being anna comnena, who was put into the care of her future mother-in-law, the dowager empress mary of alania, before she was eight years old so she could be brought up with her fiancé constantine (anna comnena, alexiad 3.1.4; cf. 2.5.1 for a further example)
 choniates, historia, 275-6.