Montgomery County leaders have had a falling out with the lawyer they had hired to file a lawsuit aimed at keeping the Barnes Foundation art museum from moving to Philadelphia.

Thomas Ellis, chairman of the county commissioners, said the dispute with attorney Mark Schwartz would not deter the county from going to court to block the move, which was approved by a judge in 2004.

But the conflict follows a decade-long pattern of sound and fury involving almost any issue pertaining to the billion-dollar collection of Impressionist art that collector Albert Barnes willed should remain exactly as it was upon his death in 1951.

Ellis said yesterday that Schwartz, of Bryn Mawr, had quit after being told Monday that the county intended to let him go.

Ellis said Schwartz had failed to inform the county of a conflict of interest he had by also representing a private group hoping to keep the Barnes in Lower Merion.

The county said it wanted back the $12,328 it had paid Schwartz.

"We basically feel we were misled," Ellis said.

Schwartz, in a phone interview, said the county knew full well that he also was representing the Friends of the Barnes - a group led by some of the museum's near neighbors, which also intends to file a suit.

"They better think long and hard before slandering or threatening me," Schwartz said, referring to county leaders.

Commissioner Ruth Damsker, the lone Democrat on a three-member county board, said she agreed with Schwartz that his dual representation of both the county and the Barnes neighbors had been clear.

The back-and-forth comments came after what, by all accounts, was an acrimonious meeting involving Schwartz, Ellis and the county solicitor, Michael D. Marino.

Damsker complained that Ellis hadn't even informed her of the meeting and called him "King Thomas."

Schwartz and Ellis had butted heads over what Ellis considered inflammatory comments in at least one draft version of a suit.

Asked what in particular had offended him, Ellis cited what he deemed a gratuitous mention that one long-ago proponent of a Barnes move - former Inquirer publisher Walter Annenberg - had a father who was a convicted felon.

Schwartz noted, however, that he had written three drafts, not one, and that anything the county objected to had been - or could be - removed. He also said the county was dragging its feet on its stated plans to sue.

Ellis said the county intends to proceed. He said the work would be taken over by the solicitor's office.

He said the main grounds for the suit would be that Barnes Foundation leaders, in asking a county judge in 2004 to permit a move to Philadelphia, failed to inform him of financial aid the state might have offered to keep it in Lower Merion.

No date has been set for the move. The Barnes has been struggling to get title to a site on the Parkway.

Nancy Herman, of the Friends of the Barnes, said yesterday that the falling out between the county and Schwartz appeared to be "miscommunication between the people involved."

She said her group and the county remained committed to going to court, even with separate suits.

"We're all in the same boat," she said.

Contact Tom Infield at 610-313-8205 or tinfield@phillynews.com.