who was he?
He was a pharaoh of the New Kingdom Nineteenth Dynasty of Egypt, the son of Ramesses I and Sitre, and the father of Ramesses II.
Seti I
Menmaatre Seti I (or Sethos I in Greek) was a pharaoh of the New Kingdom Nineteenth Dynasty of Egypt, the son of Ramesses I and Sitre, and the father of Ramesses II. 
who was unas? He was a pharaoh, the ninth and last ruler of the Fifth Dynasty of Egypt during the Old Kingdom. what are a few sources from which we get to know about him? The Abydos King List, the Saqqara Tablet and on the Turin canon. what is the former? It is a list of the names of seventy-six kings of ancient Egypt, found on a wall of the Temple of Seti I at Abydos, Egypt. mention a temple found in this place. The memorial temple of Seti I.
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Seti I [SEP] Introduction
Menmaatre Seti I (or Sethos I in Greek) was a pharaoh of the New Kingdom Nineteenth Dynasty of Egypt, the son of Ramesses I and Sitre, and the father of Ramesses II. As with all dates in Ancient Egypt, the actual dates of his reign are unclear, and various historians claim different dates, with 1294 BC to 1279 BC and 1290 BC to 1279 BC being the most commonly used by scholars today. The name 'Seti' means "of Set", which indicates that he was consecrated to the god Set (also termed "Sutekh" or "Seth"). As with most pharaohs, Seti had several names.