[Vendome]

I understand but, a sign of the cross on the seal seems odd.

You know more about this stuff than I and probably have an answer.

[lacrew]

The cross symbol was used by the Greeks, before Christ.

[SeekAndFind]

From Wikipedia:

Prior to 2000 B.C. the cross symbol, was already in use in ancient alphabets (Paleo-Hebrew [✗], Canaanite, Phoenician) as the letter 'Tau' ('Taw'/'Tav') which corresponds to the modern letter 'T' and meant 'Mark' (Its literal usage in the Torah denotes a wound). It is probably derived from two sticks crossed to mark a place similar to the Egyptian hieroglyph

[CJ Wolf]

It’s an Ankh, the other symbol also looks like a winged scarab or sun. It may have been a seal used by the egyptians to send communication to King Hezekiah which is why it showed up in Israel. (my take)

[mountainlion]

The cross looking thing with the loop on top is an Anch (sp), it is an Egyptian symbol.

https://de.wikipedia.org/wiki/Anch

[BroJoeK]

Vendome: "I understand but, a sign of the cross on the seal seems odd."

That is an Egyptian ankh, as the article says, "a symbol of life" sometimes adopted & adapted by Christians: