Casting box for unknown key

[Illiza]

Hi.
The casting box for a key was found on the rock with a dolmen in a woody forest of the Northen-Western Coucasus, in a few km from Black Sea coast. The material of the rock is sandstone. The counterpart of this pattern was not found. As you could manage,the key may have been done since the Roman period till the 18th centuary. There were numerous Byzantine, Greek and Genoese colonies on the Black Sea coast. Could anybody give the ideas about dating and appearance(origin)of this type of key. The pattern was slightly curved.
Can anybody say something?
Thanks

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ris04en..jpg

[Halflock]

It is a large ward lock that this key would have fit. I don't have much knowlage of that large and old key locks. I would imagine that it would be a simple ward lock. Maybe a cache lock or a lock to keep the hidden door closed. I have heard that in the days of old a crack in a wall would hide a lock and a large key would be used to open a hidden door.

[oldlock]

Not a typical roman style of key that I have ever seen, so must be a good deal later.

[Brian Morland]

It’s possible that this style of key might be for a spring barb type of mechanism, which is very often confused with the very similar in appearance ward tumbler types. One clue is cast bronze keys are usually for spring barbs and forged iron might be more likely for ward tumbler type locks.
Dating may have to be taken in context with other finds on site but is typical of late Roman to late Medieval.
Have you done any excavating at the site when you almost certainly you will find the spoil of other castings and maybe even other keys and lock parts.