These stirrups are made of brass or bronze with a dark aged patina.
They are very similar but they are not an identical pair

This design of stirrup is known as a bell ( estribo de campana) or crown stirrup.

The curved arches have separate fixed suspension loops. Below the pierced treads each has a metal skirt or bell.

These are decorated with cast foliate patterns
One stirrup is stamped on its side with a star.

Dimensions stirrup 1 : Width 5¼" (13.2cm), height 7" (18cm), maximum depth 3" (7.5cm)

Stirrup 2 : width 5½ (14cm), height 7½" (19cm), maximum depth 2½" (6.5cm)
Combined Weight : 2lb ¾oz (927g)

Ref : stirrup449