Why did Holly Holm stop boxing? Find out what prompted 'The Preacher's Daughter' to bring her pugilistic career to a grinding halt

After nearly a year of inactivity, Holly Holm is set to return to the octagon later this month when she faces promotional newcomer Kayla Harrison at UFC 300. 'The Preacher's Daughter's' combat sports career began as a boxer and kickboxer before transitioning into mixed martial arts.

The No.5-ranked women's bantamweight remains the only combat sports athlete to capture both a boxing and a UFC title. Despite having a very successful boxing career, Holly Holm walked away from the sport in 2013. Take a look at why she retired below.

Why did Holly Holm retire from boxing?

Holly Holm announced that she would retire from boxing ahead of her May 2013 fight against Mary McGee, which she won via unanimous decision. She announced her decision in a press conference a month before the bout, stating:

"A hard decision, but I need to keep that spark and passion, and MMA is where it’s at for me now." [h/t Sherdog]

She added:

"When we were deciding which way to go with my future, my trainer Mike [Winkeljohn] said it best: ‘You want to climb a new mountain,'. This thing has created a new spark in me, and I’m following my heart." [h/t MMA Junkie]

Holly Holm's boxing career ended with a 33-2-3 record including 16 title defenses across three weight classes. She was named The Ring Fighter of the Year in 2005 and 2006, among other awards, before retiring as BoxRec's highest-ranked pound-for-pound women's boxer of all time.

'The Preacher's Daughter' remains the promotion's highest-ranked women's welterweight of all time. Furthermore, she has earned a place in the International Boxing Hall of Fame, International Women's Boxing Hall of Fame, and New Mexico Sports Hall of Fame.

While she had made her mixed martial arts debut before she retired from boxing, compiling a 3-0 record, Holm's career took off after she made a full-time commitment to the sport. She won her next four bouts before making her promotional debut at UFC 184 in February 2015.

After winning her first two fights in the promotion, she received a title opportunity at UFC 193 in November 2015. Holm's decision to move to MMA paid off as she defeated Ronda Rousey via second-round knockout to capture the women's bantamweight title.

She earned Fight of the Night and Performance of the Night bonuses and later earned 2015 Newcomer of the Year, Upset of the Year, and Knockout of the Year honors.

The victory remains one of the biggest upsets in promotional history, while 'The Preacher's Daughter' has one of the quickest rises from debut to a title. Holm remains the only fighter to capture both a boxing and UFC title.