If you look at a can of jalapenos, you'll probably see the words en escabeche on the label.
Escabeche comes from the Moors, who occupied Spain for almost 800 years, bringing many of their Near Eastern dishes with them. One was sikbaj , which was so essential to a banquet in the Middle Ages that it was nicknamed "the father of hospitality."
Sikbaj is a Persian word meaning "vinegar stew," and most medieval recipes describe it as lamb stewed with vinegar and spices.
There is also a 13th-Century Arab recipe for "fish sikbaj -style"--fried fish marinated (virtually pickled) in vinegar with saffron and celery leaf. In Spain, the meat escabeche died out, but fish escabeche survived. Catalans from northeastern Spain introduced it to southern Italy, where the 13th-Century recipe is still followed in making scapece Vastese .
The Spanish may have been interested in the fish version because, as Christians, they were always in need of meatless dishes for Lent and other fast days. This may also be why they developed vegetable escabeches , paving the way for the Mexican version made with jalapenos.