PHILADELPHIA — A court fight over control of Philadelphia’s two largest newspapers shows the owners’ feud has been escalating for nearly a year, while their publisher went part-time, working from Florida.

Co-owners Lewis Katz and George Norcross, both wealthy powerbrokers in the region, have sued each other over control of The Philadelphia Inquirer and Philadelphia Daily News.

On the witness stand Thursday, Katz said Norcross has sought to fire editor Bill Marimow since January. Katz backs Marimow and refused to sign off on the move. However, Marimow was fired last month by publisher Bob Hall, who has sat beside Norcross during two days of ugly court testimony this week.

“Mr. Norcross felt that Mr. Marimow should be fired because he wasn’t a leader, … (and) he was resistant to change,” Katz testified.

Katz has asked a judge to return Marimow to the newsroom, and oust Hall. Norcross has countersued.

Their rival lawsuits are being fought by at least 18 lawyers, including Philadelphia legal warrior Richard Sprague for Katz and former Homeland Security secretary Michael Chertoff for Norcross.

Marimow testified Wednesday that he was fired after refusing to fire five veteran editors. Katz elaborated, saying the newsroom targets had tangled with members of Norcross’s family.

Norcross’ daughter, Lexie, runs the Philly.com website. Katz has his own personal link to the newsroom, longtime companion Nancy Phillips, a veteran reporter who testified that she facilitated Marimow’s hiring as Katz and Norcross negotiated to buy the company last year. Phillips has since become city editor under Marimow, who won two Pulitzer Prizes — the nation’s top honor in newspaper journalism — during several stints at the Inquirer.

The newspapers have had five owners in seven years, a period when their value dropped from $515 million to $55 million, and workers endured layoffs and pay cuts.

Katz and Norcross invested $16 million apiece toward the $55 million purchase in April 2012, and hold 26 percent stakes. Four other business leaders made smaller investments. But Katz and Norcross set up a two-man management committee to control key business decisions. Katz thought that would force them to get along.

“(Otherwise), Norcross would have full power over the whole operation, including the newsroom,” Katz said. “We would be where we are today, in a terrible situation.”

Katz, a former Democratic party leader in Cherry Hill, N.J., made his money in parking lots and real estate, and also owned the New Jersey Nets. Norcross is an insurance executive and powerful New Jersey Democrat. They had never done a deal together before, Katz said.

His testimony resumes Thursday afternoon before Common Pleas Judge Patricia McInerney.