Iron forged, and originally engraved (some remnants of the engraving are still visible).
To open, you have to press away a small plate at the bottom right, the cover of the keyhole then springs open.
Forged iron.
Collection LIPS
Published - Locks and Keys Throughout the Ages - Vincent J.M. Eras - page 97 - ill. 164
Key: 11,7cm
Padlock: 13cm x 8cm x 4,5cm
Beard: 5,9cm x 2,6cm