In June 1992, many wrestlers left CMLL to join the newly formed Asistencia Asesoría y Administración ("Assistance, Assessment, and Administration"; AAA), which significantly affected CMLL's middleweight championships. The Mexico City Boxing and Wrestling Commission allowed AAA to assume control of the Mexican National Middleweight Championship as the reigning champion Octagón had joined AAA. Meanwhile, the CMLL World Middleweight Championship was vacated after the departure of the champion, Blue Panther. CMLL held a 16-man battle royal match to reduce the field to two finalists. El Dandy and Negro Casas survived the match, and a week later El Dandy defeated Casas to become the second CMLL World Middleweight Champion. The championship has not been vacant since then.