So im no expert but recently i was watching a show on history channel called pirate treasure of the knights templar, and it looks very similar to a chest they showed in that and they said it was a form of a burial chest that the templars would use as a holy box and the 8-point cross on top is a common symbol of templars. The reason i say this is the cross on the top looks similar to the ones shown on the tv show. Here is a similar box i found on google thats much newer and made of wood and another much older made of stone.
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Here are some examples as well of templar crosses.
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