Ancient Celtic (probably) or Roman brooch (fibula) from an old collection of Celtiberian items

An ancient brooch, known as a fibula, from a collection of Celtiberian items (see more info below). Of note, if you look at the main picture you'll see some yellowish color at the bottom of the bow, and at the top of the bow just at the turn, in the right light these tiny spots these have a little sparkle, revealing that many years ago this brooch was likely gold in color. This brooch is missing the pin/catch system). A unique design, the bow with its spinelike ridgeline, is more standard to Roman brooches, but the four-balled plate may reflect the Celtiberian influence.

This brooch is from a Celtiberian collection of bronze artifacts, it is made of bronze and it measures approximately 35 x 32 x 23 mm.

Provenance -

On the inside, someone wrote "Eslava". This likely coincides with the Roman site of Santa Criz de Eslava, halfway between Tafalla and Sanguesa in Spain.

We bought a collection of artifacts at auction in Switzerland (La Galerie Numismatique, September 28th, 2024); we are researching each object and offering them for sale individually. You can see the collection in the pictures we posted.

In the course of our investigation, we found that the artifacts had names of places in the Celtiberian region written on them, for example "Salienca". Also, the larger brooch design was unique to the Celtiberians (Google search "Celtiberian Fibula" to see similar examples). We've come to the conclusion that the collection is specific to the Celtiberian era/region.

Wikipedia tells us the Celtiberians "were a group of Celts and Celticized peoples inhabiting an area in the central-northeastern Iberian Peninsula during the final centuries of the BC. They were explicitly mentioned as being Celts by several classic authors (e.g. Strabo)."

Condition -
See pictures. Bronze is tarnished to green, with some dirt still on it. Brooch is bent. Missing pin/catch system. Someone wrote the place name on it. There are some traces of glue where it was glued to the collection. There is a crack where the bow turns down.