In a heated hearing Thursday morning, a Manhattan civil judge told representatives of a New York performing arts venue to adjust their expectations in the venue’s effort to evict a tenant of 120 years — the Knickerbocker Greys, a youth cadet corps.

“What you think is going to happen and what is going to happen are two different things,” Judge Hilary Gingold told the arts group, the Park Avenue Armory Conservancy, who are seeking in Manhattan civil court the eviction of the youth group.

Judge Gingold noted “issues of fact” were in dispute in the case and said she did not foresee an easy settlement and would not grant a court-ordered eviction.

The hearing was the first court appearance in the eviction suit filed by the Armory Conservancy against longtime occupants of the Armory, the Knickerbocker Greys.

The Greys, who have been called the Upper East Side’s “little patriots,” describe themselves as America’s oldest after-school program, training and serving students in middle and high school. The group boasts distinguished alumni including Mayor Lindsay, Vice President Rockefeller, and Douglas Fairbanks, Jr.

The Armory Conservancy, which began leasing the historic Park Avenue building in 2006, first demanded this spring that the Greys vacate their premises by June 1 and sent an official ten day eviction notice on August 18.

In a stunning claim in this morning’s hearing, the president of the conservancy, Rebecca Robertson, claimed that, to her knowledge, the Greys had only been in the building since 2004 — which was the group’s 102nd year on-site.

Ms. Robertson claimed the tenants had been evicted in 2006 by the state’s Division of Military and Naval affairs, which the Greys dispute. The president of the Knickerbocker Greys’ board, Adrienne Rogatnik, says the notice informed the Greys not of an eviction but of a transfer of responsibility. The letter told tenants they would be evicted in the absence of a lease.

“[I]f your organization desires to continue meeting periodically within the armory, you must now make appropriate arrangements with the Conservancy which will set all rules and regulations for access to the Armory hereafter,” says the letter. Since the transfer of responsibility, until now, the Greys have remained in the Armory under interim arrangements with the Conservancy.

“They knew their lease was temporary,” Ms. Robertson said at the hearing.

“When I hear an entity has been in place for 120 years… I don’t think that’s temporary,” Judge Gingold said from the bench.

The Armory Conservancy claims, in addition to the more than 200,000 square feet in use, it needs the 800 square foot basement that the Greys occupy to create an Americans with Disabilities Act-compliant entrance. The venue currently has a handicapped accessible entrance on East 66th Street.

Representatives for the Greys did not have legal counsel because, they said, they received only the cover letter to the suit on October 17, without the rest of the suit documents, via email. The group claims “improper service” of the court documents, since they could not access their mailbox in the Armory, due to the ongoing dispute.

The two parties will return to court on January 10, with “plenty of time,” as the judge said, for the Greys to get a lawyer, give an answer, and, she suggested, try to settle without trial. The Greys expressed to Judge Gingold the hope in the meantime they might be able to drill in the Armory.

The Armory’s press representatives did not respond to a request for comment by the time of publication.