Usurped Cartouches Key to Discovery
The inscriptions that accompany the reliefs on the Karnak wall actually tell us which pharaoh the scenes glorify, but the vital clues have been partially destroyed and hence long overlooked. The key lies in the inscriptions’ cartouches—the oblong rings that enclose the pharaoh’s fourth and fifth names (the prenomen and nomen)—which have been usurped, that is, partially erased and recarved with the name of a later pharaoh. Frank Yurco successfully identified the sequence of usurpation by discovering that the original cartouches of Merenptah (1212–1202 B.C.E.) had been usurped by Amenmesse (1202–1199 B.C.E.), whose cartouches were in turn usurped by Sety II (1199–1193 B.C.E.). The usurpation process consisted of shaving and then scoring the earlier cartouche to improve the hold of a coat of plaster, on which the new cartouche could be carved. Fortunately for history, this process failed to entirely obliterate the earlier cartouches, because the shaving did not reach the full depth of the original engraving and the plaster has fallen off in places.
Superimposed cartouches
Merenptah
Amenmesse
Sety II
Traces of Merenptah’s and Amenmesse’s usurped cartouches appear in the cartouches in this detail from scene 2. The drawings show these cartouches as they appear today as well as the cartouches of the three pharaohs (Amenmesse’s prenomen is omitted because the traces of it are too difficult to read). By comparing the three pharaohs’ cartouches to the extant cartouches on this exemplar, we can see that the latter is a composite of elements from the former. Slight remnants of the 
and 
of Amenmesse’s nomen can be seen in the extant cartouche, the former just above the 
of Sety II’s nomen, and the latter to the left of the 
of Merenptah’s nomen.
Surviving signs from Merenptah’s cartouches are more abundant and clear, because they were more deeply engraved than Amenmesse’s cartouches. Almost the whole bottom half of Merenptah’s nomen is still visible, as well as part of the 
from the upper portion of his nomen. From Merenptah’s prenomen, the legs of the 
clearly remain below the 
from Sety II’s prenomen.