Theodora also created her own centers of power. The eunuch Narses, who in old age developed into a brilliant general, was her close ally, as was the praetorian prefect Peter Barsymes. John the Cappadocian, Justinian's chief tax collector, was identified as her enemy, because of his independent and great influence, and was brought down by a plot devised by Theodora and Antonina. She engaged in matchmaking, forming a network of alliances between the old powers, represented by emperor Anastasius' family and the pre-existing nobility, and the new, who were Justinian's and her relatives. According to "Secret History", she attempted to marry her grandson Anastasius to Joannina, Belisarius' and Antonina's daughter and heiress, against her parents' will, although the couple would eventually fall in love with each other. The marriages of her sister Comito to general Sittas and her niece Sophia to Justinian's nephew Justin II, who would succeed to the throne, are suspected to have been engineered by Theodora.