Cloth Seal, Dutch, Leiden, Early 15th Century

Cloth Seal, Dutch, Leiden, Early 15th Century, Image & Found by Kees Essaadi.
Found near Amsterdam, 30mm, 31.6g.

Crossed keys L ST to sides // OVDE / (L)EITS / STAEL

It is an old and very rare one, probably around 1400/1450

From the finder, "It shows the keys of the city of Leiden, and the keys are squared, indicating that this seal is very old. It also shows the characters L and S. they stand for Leits Stael (which is the quality indicator)
On the other side is says ‘oude leits stael’ (old Leiden stael)."

The stael mark usually applies to cloth that has met certain dying standards.