Dec. 21 was supposed to bring doomsday, the apocalypse, Armageddon; but it turns out the Mayan’s calendar conclusion in 2012 contrarily marked the beginning of a new era in hip-hop, the Pro Era.

Dec. 21 was the aPROcalypse.

Pro Era’s debut mixtape, “PEEP: The aPROcalypse,” was a perfectly timed release. The crew’s frontman, Joey Bada$$, sparked heavy interest in the more than 20 members of Pro Era with his freshman mixtape release, “1999,” just six months prior.

Capital Steez quickly emerged on Joey’s “1999” tape as one of Pro Era’s most talented and radical members with verses in “Survival Tactics” and his music video for “Free The Robots.” The 19-year-old Steez committed suicide just three days after “PEEP: The aPROcalypse” was released and received positive reviews.

“PEEP: The aPROcalypse” is by no means focused on any one member of the Brooklyn collective. Joey and Steez kept the pace throughout the mixtape as Kirk Knight, CJ Fly and other members effortlessly filled their voids with fluent verses.

The cohesiveness in each song sticks out immediately after one listen. The relationship of the crewmates shines through as each track sounds like it was merely a freestyle cipher at an Edward R. Murrow High School lunch table, the meeting place of a majority of the band members.

The production enviably returns to the Era’s signature boom-bap, ‘90’s sound. Instrumentals from long-time, East Coast producer, Statik Selectah, and in-house production from Chuck Strangers solidify the young crew’s signature sound.

It may be unfair to feed in to the Joey-Nas comparisons, but much like the passing of Steez, Nas lost his best friend, Ill Will, early in his career and it proved to have an impact on him and his music while recording “Illmatic.”

“Illmatic” turned out to be arguably one of the best hip-hop albums ever and Nas payed homage to Ill Will with numerous mentions about him in his lyrics. The same realization of, “tomorrow is never promised,” may positively impact Joey in the same way it did Nas.

Dec. 21 resulted only in the end of doubt in one of hip-hop’s best and youngest groups. Sure they may be a bunch of teenagers with “old souls,” but that old-soul mentality is what created and continued hip-hop since day one.