Egyptian Museum, Cairo.
Apart from being a relatively unusual and gorgeous find, this piece poses a riddle: the king Ḥeqakheperrēʿ-setepenrēʿ Šōšenq-meryamūn, whose names are engraved on the hawk-headed silver coffin, though tentatively identified, for a long while now, as Šōšenq II (a designation for which there are other candidates), is not known from any other source.
Apart from the coffin and three accessory pieces, all the other pieces found used in this burial belong to the founder of Dynasty 22, Ḥeḏḫeperrēʿ-setepenrēʿ Šōšenq-meryamūn, whom we call Šōšenq I (r. 943–922 BC, probably).
A recent study by Broekman (Göttinger Miszellen 254, 2018) made a strong argument for interpreting the evidence as indicative of a later transfer of Šōšenq I from an original entombment somewhere else to NRTIII tomb at Tanis (alongside several earlier royals). The silver hawk-headed coffin would have been made on this occasion, replacing the original, for whatever specific reason. The change in the royal name found on the new coffin remains surprising, with possibilities ranging from a mistake to a purposeful alteration (perhaps especially if the king responsible for the transfer and reburial was Takelōt I, who bore the same throne name, Ḥeḏḫeperrēʿ-setepenrēʿ).