Complex sentence: Tia or Tiya was an Ancient Egyptian princess during the 19th dynasty; the daughter of Pharaoh Seti I and Queen Tuya and the elder sister of Ramesses II. She is attested only on monuments dating to Ramesses' reign.
Split into simpler sentences: Tia or Tiya was an Ancient Egyptian princess during the 19th dynasty. Tia was the daughter of Pharaoh Seti I and Queen Tuya and the (older) sister of Ramesses II. She is attested only on monuments dating to Ramesses' reign.