In 51 BCE, following the death of Ptolemy XII Auletes, eighteen-year-old Cleopatra VII ascended the Egyptian throne as co-ruler with her ten-year-old brother Ptolemy XIII, as stipulated in their father's will. By August 51 BCE, official documents listed Cleopatra as sole ruler, indicating she had sidelined her brother. This power consolidation provoked opposition from Ptolemy's advisors, including the regent Potheinos and military commander Achillas, eventually triggering a civil war between the siblings.