The next theory reduces the age of the Exodus further: it has for its cornerstone a stele of Merneptah, in which this king of the Nineteenth Dynasty says that Palestine "is a widow" and that "the seed of Israel is destroyed." This is regarded as the earliest mention of Israel in an Egyptian document. Merneptah did not perish in the sea, nor did he suffer a debacle; he obviously inflicted a defeat on Israel and ravaged Palestine. The circumstances do not correspond with the pronounced tradition of Israel, but since it is the first mention of Israel, Merneptah is regarded by many as the Pharaoh of the Exodus (about 1220), and Ramses II, his predecessor, as the Pharaoh of Oppression. 15 Other scholars, however, consider the mention of Israel in Palestine in the days of Merneptah not as a corroboration, but as a refutation of the theory that Merneptah was the Pharaoh of the Exodus. They argue that if he found Israel already in Palestine, he could not have been the Pharaoh of the Exodus. [p.9]...
They are believed to have left Egypt in the days of Merneptah (though his stele mentions Israel as already in Canaan), but they did not appear iu Palestine until after the invading Philistines, with whom Ramses III battled. Accordingly, the invasion of Palestine by the Philistines is put some fifty years after the Exodus and a few years before the conquest of Canaan by Israel....
The arrival of the Israelites in Palestine in the days of Merneptah., and still less in the days of Ramses III after his campaign there* in 1186, leaves no room for the events of the Judges who guided the people for four centuries prior to Saul and David... [p.10]
It is appropriate here to explain the name "Retenu" or "Rezenu" often employed in the Egyptian inscriptions of the New Kingdom to designate Palestine. Galilee is called "Upper Rezenu." "Rezenu" is apparently a transcription of the name used by the population of Palestine for their land. The Hebrew language must be questioned on its meaning.
In the Scriptures Palestine is frequently called "Erez" ( country ), "Erez Israel" (the land of Israel), and "Arzenu" (possessive case, "our country"). What the Egyptologists read as Retenu or Rezenu is probably the "Arzenu" of the Bible.
In only one inscription of the Middle Kingdom (Twelfth Dynasty) under Sesostris III is the name Rezenu mentioned it is a very short account of a raid into that country against M-n-tyw. As we shall find the same name, Mntyw, in Egyptian documents of a much later period, that of King Menashe (Manasseh), the Mntyw of the Middle Kingdom must mean the tribe Menashe. If the inscription is correctly attributed to the time of Sesostris III, the mention of the tribe Menashe would imply that before the Israelites had come to stay in Egypt they had dwelt in Palestine, not as a single patriarchal family, but as tribes strong enough to be regarded as enemies by the pharaoh. This would accord with the tradition of a defeat inflicted by Abraham and the servants of his household on the kings of Shinar and Elam and their allies (Genesis 14), and with the number of the Israelites (about two million, including women and children) in the days of the Exodus, after some two hundred years of sojourning in Egypt. [pp.173-4]
Can't prove it but I've long thought that Radhanite was derived from Retenu.