The world of professional wrestling has lost a true legend.

Miguel Ángel López Díaz, better known by his ring name Rey Misterio Sr., has died at the age of 66, according to a statement from his family.

Lucha Libre AAA Worldwide also released a statement following the news.

“We regret the sensitive death of Miguel Ángel López Días, known as Rey Mysterio Sr.,” the promotion said in a statement (translated from Spanish). “We express our sincere condolences to his loved ones and pray to heaven for his eternal rest.”

Misterio Sr. is best known these days for training his nephew Rey Mysterio, one of the most popular professional wrestlers of all time.

In addition, Misterio Sr. trained other professional wrestling legends such as Konnan, Psicosis, Halloween and Damian 666. He also trained his son Rey Misterio Heredero, better known as El Hijo de Rey Misterio.

Misterio began his professional wrestling career after training as a boxer. He made his in-ring debut on January 6, 1976 at Día de los Reyes, translated as “Day of the Kings.”

Misterio became extremely popular in Mexico and competed in several promotions including Lucha Libre AAA Worldwide, Pro Wrestling Revolution, Tijuana Wrestling and World Wrestling Association (WWA).

Misterio also appeared in World Championship Wrestling (WCW) as part of the “Pat O’Connor Memorial International Cup” during the Starrcade pay-per-view in 1990. He represented Mexico alongside Konnan.

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Misterio has won several titles, including the IWC World Middleweight Championship twice, the America’s Championship, the Tijuana World Welterweight Championship and the WWA World Junior Light Heavyweight Championship.

In addition to his singles titles, Misterio won the WWA Tag Team Championship with his nephew and the Revolution Tag Team Championship with his son.

Misterio was inducted into the Tijuana Sports Hall of Fame in 2006 and retired from professional wrestling in 2009. Nevertheless, he fought his last fight in 2023.

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The wrestling legend has received numerous honors.

“I am so sorry to hear of the death at age 66 of the original Rey Misterio (Sr.), Miguel Lopez, the WWE star’s uncle,” said Dave Meltzer of Wrestling Observer. “At his peak, he was almost like Tijuana’s version of Jerry Lawler in Memphis.”

@elClubLucha re-shared a compilation video they made of the Rey Misterio Sr. and Rey Mysterio Jr. collaboration and simply said, “RIP Rey Misterio Sr.”

Everyone here at Newsweek Sports sends condolences to Misterio’s family and friends.