Ptolemy XII died sometime before 22 March 51 BC, the date of Cleopatra's first known act as queen: her voyage to Hermonthis, near Thebes, to install a new sacred Buchis bull (worshiped as an intermediary for the god Montu in ancient Egyptian religion).[114][115][116][note 24] The Roman Senate was not informed about Ptolemy's death until 30 June or 1 August 51 BC; the news may have been suppressed by Cleopatra until she could secure the throne.[117][118][note 25] Cleopatra probably married her brother, Ptolemy XIII,[100] but the marriage is uncertain.[115] The incestuous Ptolemaic practice of sibling marriage was introduced by Ptolemy II and his sister, Arsinoe II, but the long-held royal Egyptian practice was considered scandalous by contemporary Greeks.[46][47][119] Although vocal critics of this incestuous practice were sometimes violently punished and suppressed during the joint reign of Ptolemy II and Arsinoe II,[note 26] sibling marriages were nevertheless considered a normal arrangement for Ptolemaic rulers by the time of Cleopatra's reign.[46][47][119] Official documents began listing Cleopatra as sole ruler by 29 August 51 BC, evidence that she had rejected her brother as a co-ruler.[120][121][122]