The Cortez brand name was established around 1960 by Jack Westheimer, a Chicago based importer and distributor. Westheimer first used the Cortez brand for a series of Japanese made good-quality Martin-style dreadnought acoustics. Most Cortez electric guitars were Strat and Les Paul copies, many made by Matsumoku. Also Cortez copies of the Gibson ES-175 were made. Cortez guitars were always made in Japan and the Cortez brand contimued until around 1986. There were also Cortez branded Italian made mandolins, but it is unclear whether these were made for Westheimer.

Source: Jack Westheimer: Pioneer of Global Guitarmaking. By Michael Wright. Vintage Guitar Magazine