There is some disagreement over when Amenmesse ruled, and whether he ruled before Seti II legitimately, or whether he usurped the throne from his brother. It is possible that Seti II was simply gone when his father died and Amenmesse stepped in to fill the role, but he ruled for 3-4 years, and Seti II had his inscriptions nd name erased which is usually a sign of an illegitimate rule. It's possible he took the throne by force in the middle of Seti's reign, as well, or only ruled part of Egypt in a bid for the throne.

Another theory is that he was a vizier of southern Egypt during the time of Seti II by the name of Messiu, and not a king in his own right at all.

There are suggestions that he was the son of Takhat, a wife/daughter of Ramesses II, but this is not supported by evidence that her name was added to the tomb later in Dynasty 20.

Nothing is known of any military or political activity for this pharaoh, and his building program is limited to a few additions to existing monuments and some statues. Six statues are attributed to Amenmesse, on the axis of the hypostyle hall at Karnak, but these were taken over by Set II.

HIs tomb, in the Valley of the Kings, is currently being excavated. It has been open since antiquity and is well known, although most of the decorations have been destroyed. Three mummies were found in the tomb: two women and a man. They have not been identified, although it is suggested that they are indeed Takhat, Baketwerel, and Amenmesse. However, many of the items found in the tomb were from later eras.

Links

Ramesses I
Seti I
Ramesses II
Merneptah
Amenmesse
Seti II
Siptah
Tawosret
Bay

monuments

Tomb KV 10, Valley of the Kings