The marriage between rap mogul Jay Z's Roc Nation Sports, a newcomer to the boxing promotional scene, and longtime promoter Gary Shaw lasted barely a month.

Roc Nation Sports entered the boxing business in August and the day before it promoted its first card on Jan. 9 at the Theater at Madison Square Garden in New York, Shaw sold his company to Roc Nation Sports and went to work for it. Shaw had moved into the Roc Nation offices in New York, brought his staff with him and worked the card last month.

He was in the process of finalizing the assignment of many of his fighter contracts from his old company, Gary Shaw Productions, to Roc Nation Sports. But things were not going smoothly -- there was plenty of infighting at the company, according to various sources -- and they decided to part ways in a surprising move.

As part of that agreement, Shaw resigned from the company on Friday and they are in the process of completing their separation in a deal in which Shaw will leave with his fighters and staff and continue doing business as Gary Shaw Productions.

"We gave it a try and unfortunately it did not work out for both parties," Shaw told ESPN.com on Monday. "It is an amicable separation. Roc Nation was very professional at our meeting and they allowed me to keep all of my fighters and my company, and terminate any agreements we had together. They gave me back my company."

Roc Nation Sports spokesman Ron Berkowitz told ESPN.com, "Both parties decided to go their own way and we wish Gary nothing but the best."

The biggest immediate byproduct of the split is that Roc Nation Sports will not be involved in heavyweight contender Bryant Jennings' title challenge against world champion Wladimir Klitschko on April 25 (HBO) at Madison Square Garden in New York.

Jennings (19-0, 10 KOs), Shaw's highest-profile fighter, was the key fighter Roc Nation Sports acquired in the initial deal to buy Shaw's company. Now Roc Nation will be nowhere to be seen when the formal news conference to announce the bout takes place on Wednesday at Madison Square Garden.

Among the fighters Shaw promotes -- who now won't be joining Roc Nation Sports -- are Jennings, interim lightweight titlist Darleys Perez, middleweight contender Tureano Johnson, lightweight Jonathan Maicelo, lightweight prospect Kenneth Sims Jr., welterweight Francisco Santana, unbeaten junior featherweight Roman Morales and former middleweight titlist Daniel Geale.

Other fighters Shaw promotes, including welterweight contender Thomas Dulorme and junior lightweight contender Jose Pedraza (who he co-promotes with Lou DiBella and Javier Bustillo), were not going to join Roc Nation Sports in the first place.

Roc Nation Sports' boxing department will continue to be run by chief operating officer David Itskowitch.

Roc Nation Sports' second card is expected to take place in March as part of its three-fight deal with Fox Sports 1.