Once upon a time — a lifetime or two ago — I was a big boxing fan.

Cassius Marcellus Clay Jr. would win the heavyweight boxing championship in 1964, change his name to Muhammad Ali and then dominate the sweet science for, oh, the next 15 or so years.

Yeah, he was stripped of his title for more than three years over his religious objection to the Vietnam War. Even then, he was The Man.

Boxing eventually took a turn away from the simplicity of the sport. It formed a lot of governing boxing authorities. Each of them recognized their version of “world champion.” They expanded the number of weight classes. There were so many “world champions,” no one could keep track of them. Some of these weight classes are topped by something called “interim champion,” whatever the hell that means!

Now the sport has come to a new level of carnival spectacle. It has scheduled a match between a retired “world champion” and a mixed martial arts goon. The boxing/MMA world is agog over the prospect of former champion boxer Floyd Mayweather fighting MMA champ Connor McGregor sometime this year.

Who’s going to win? I don’t know and I don’t care.

I do know that boxing has now resorted to creating circus acts to gin up attention for a sport in serious decline.

If only we could return to the era when the heavyweight boxing champion of the world was the baddest man on Earth.

Oh, do I miss Muhammad Ali.