Complex sentence: Even so, Matthias nominated her nephew, the 8-year-old Ippolito d'Este Archbishop of Esztergom, although the Pope refused to confirm the child's appointment for years.
Split into simpler sentences: Even so, Matthias nominated her nephew, the 8-year-old Ippolito d'Este Archbishop of Esztergom. The Pope refused to confirm the child's appointment for years.