We usually think that there is a strong lack of documents on the subject about mourning in ancient Egypt. But the more we visit museums all over the world, the more examples we find. The point is that we need to look even at the smallest pieces and also watch at them.
Here we have a piece of a rishi coffin in the Metropolitan Museum of Art in New York. It is small, with incomplete decoration and with no inscriptions, so it could be of no relevance. Probably visitors ignore it, but it is extremely important for our subject about mourning women in ancient Egypt and their mourning ritual in the Egyptian funerary ceremony.
It comes from the debris area in the Royal Cache TT320 (also known as DB 320 for being next to Deir el-Bahari temples) and it is dated at the end of the XVII dynasty and the beginning of the XVIII dynasty.
The decoration of this small piece of wooden coffin shows the Egyptian mourning ritual made by five women. Three of them are on the left standing with crossing arms on their chests. On the right side, the mummy is flanked by two other mourning women. Although the whole bodies are incomplete, we can guess from their hips that both are bending over the corpse. The lower part of the mane of hair in the mourner on the left is still visible and from it we could deduce that she would be making the typical Egyptian nwn gesture of shaking the hair forwards. Most probably her fellow on the right was making the same gesture.
This would remind us the scene of the stele of Abkaou in Louvre Museum and dated in the XI dynasty, where the two mourners during the rites of the Osiris festivities are bending and shaking hair towards the mummy. The difference here is that it is royal mummy. In that case it reminds the scene in the funerary temple of Seti I in Dra Abu el-Naga, where the two mourners are bended and making the nwn gesture towards the king’s corpse.
With all these data we could deduce that this small fragment of painted wooden from the Metropolitan Museum of Art shows the two mourners in the role of Isis and Nephtys, so the Drty, performing their ritual mourning and shaking the hair forwards, which was a part of the Opening of the Mouth ceremony, over the Pharao’s mummy.
 The TT 320 was built in XXI dynasty for hiding the mummies of kings, queens, royal relatives and Egyptian noble men; all of them dated from XVII dynasty until XXI dynasty.