From Mixed Martial Arts wiki--

The first state-regulated MMA event was held in Biloxi, Mississippi on August 23, 1996, with the sanctioning of IFC's Mayhem in Mississippi[66] show by the Mississippi Athletic Commission under William Lyons. The rules used were an adaptation of the kickboxing rules already accepted by most state athletic commissions. These modified kickboxing rules allowed for take downs and ground fighting and did away with rounds, although they did allow for fighters to be stood up by the referee and restarted if there was no action on the ground. These rules were the first in modern MMA to define fouls, fighting surfaces and the use of the cage.

In March 1997, the Iowa Athletic Commission officially sanctioned Battlecade Extreme Fighting under a modified form of its existing rules for Shootfighting. These rules created the three 'five-minute round/one-minute break' format, and mandated shootfighting gloves, as well as weight classes for the first time. Illegal blows were listed as groin strikes, head butting, biting, eye gouging, hair pulling, striking an opponent with an elbow while the opponent is on the mat, kidney strikes, and striking the back of the head with closed fist. Holding onto the ring or cage for any reason was defined as a foul.[67][68] While there are minor differences between these and the final Unified Rules, notably regarding elbow strikes, the Iowa rules allowed mixed martial arts promoters to conduct essentially modern events legally, anywhere in the state. On March 28, 1997, Extreme Fighting 4 was held under these rules, making it the first show conducted under a version of the modern rules.[citation nee