> the Spanish for “bandit,” “helmet,” and “truce.”

If they are bandido, casco, tregua they are identical to the Italian bandito, casco, tregua. The only difference is a d/t. Actually in Italy a cyclist and a worker wear a casco, but a soldier wears an elmetto.

I googled the etymology of casco and it comes from Latin but it came to Italy from Spain a few centuries ago. So I wonder what other word for helmet they use in Spain, that originated in the Goth language.