The initial story about the Catteni preceded the books by many years. The Thorns of Barevi first appeared in 1970 (and is included in the collection Get Off the Unicorn, 1977).
An earlier story about the Catteni was published before the novels, and it was titled "The Thorns of Barevi," which debuted in 1970 and has since been reprinted in the anthology "Get Off the Unicorn" in 1977.