These shoe shaped stirrups are made of brass.
In English they are often called "Conquistador" stirrups, but they probably date from the 19th Century.
The shape would protect the rider's feet from injury.
Both stirrups are decorated with a buckle pattern on the front and a disc below a fan or plume  on each side .
There are two triangular drainage holes in the base of each stirrup.

A previous owner has written "Antioquia,Columbia,South America" on the underside of one stirrup.
These were working tools and there are various dents, dings and small splits to the metal and one has been squeezed so that it is a little narrower than the other.

Dimensions : External Width 4" (10cm), height 5" (12.5cm), length 10½" (26.8cm)
Weight : 2kg (4lb 7oz )

Ref : stirrup417