This somewhat damaged piece is a rare survivor of a strange design which resurfaces in the 18th and 19th centuries in silver, in England at any rate. The rowel spur first appeared in the 14th century and normally had fixed arms, as opposed to hinged ones.

This type of spur would have been worn in the Crusader armies in the early Middle Ages. They were really only superceded when the new style Gothic spurs appeared, with much longer shanks and the introduction of rowels in the 14th century.

This is probably a north European item and the ironwork would indicate that it was fixed to the horseman's boot permanently (the two small projections at the top would appear to be iron staples/nails that would have been fixed into the heel of the boot). It probably had a small 1cm-diameter spike rowel, now largely disappeared.

This type of spur would have been worn in the Crusader armies in the early Middle Ages. They were really only superceded when the new style Gothic spurs appeared, with much longer shanks and the introduction of rowels in the 14th century.