He was foaled in Florida out of the Minnesota Mac mare, Roundup Rose, sired by the 1969 American Horse of the Year, Arts And Letters.
[2] Codex, ridden by Ángel Cordero Jr., beat the Kentucky Derby-winning filly, Genuine Risk by 43⁄4 lengths in the 1980 Preakness Stakes, becoming Lukas' first Triple Crown-race winner.
[2] One of Codex's lawyers, Arnold M. Weiner, displayed photos showing the horses almost feet apart in contrast to the television footage.
[3] After testimony by dozens of witnesses, the Maryland Racing Commission ruled that any contact was incidental and allowed the result to stand.
From Codex's 1982 (first) crop came Tartan Stable's Coup de Fusil who emulated her sire by winning three straight Grade I races.