Sanders (defendant), in prison at the time, was charged with assault with a dangerous weapon and possession of a contraband shank. Sanders took the stand and claimed self-defense on the assault charge. At trial, the prosecution sought to introduce into evidence Sanders’s previous convictions for assault and possession of a contraband shank. The trial court allowed the prosecution to question Sanders about the prior convictions under Rule 609. The trial also allowed the questioning under Rule 404(b), claiming that the previous convictions were evidence of Sanders’s intent in the current case. Sanders was convicted on both the assault and possession charges. He appealed.