A group that served as guardians of the Alamo for more than a century before the state of Texas announced it was taking over day-to-day management of the historic site is suing for control of more than 30,000 books and artifacts at its library.

The Daughters of the Republic of Texas filed suit Monday against the Texas General Land Office, alleging the agency "unilaterally declared" the state owner of the organization's private library collection after Land Commissioner George P. Bush announced that he was ending the group's management of the downtown San Antonio mission-turned-fortress.

The suit maintains that the items in question were donated to the Daughters — who began caring for the Alamo in 1905 — and that the donors wanted the items to be maintained under the group's stewardship, not the state's. The group accuses the General Land Office of "an unlawful attempt to take the organization's private property."

A spokeswoman for the General Land Office said the agency doesn't comment on pending litigation.

The Alamo was the site of an 1836 battle in the Texas Revolution in which some 180 defenders were killed during a siege by Mexican forces. Weeks later, those deaths provided Texas soldiers with their rallying cry — "Remember the Alamo!"— that they carried to victory at the Battle of San Jacinto, which clinched Texas' independence from Mexico.

The General Land Office took ownership of the Alamo in 2011 at the behest of the Legislature, which had grown concerned about the care of the Texas landmark. Worries arose following accusations of mismanagement and financial incompetence levied at the nonprofit Daughters. However, even after the state took ownership, the group had continued managing the site.

In announcing the management change on March 12, Bush had said that his office would solicit proposals for the development of a strategic plan for the Alamo grounds and search for a new management company.

The Daughters' lawsuit focuses on the collection within the research library, which was established in 1945. In the lawsuit, the group said it owns more than 77 percent of the collection, made up of some 38,000 items, including books, maps, flags, and other artifacts used by researchers.

Ellen McCaffrey, president general of the Daughters of the Republic of Texas, said part of the collection is stored in a vault within the library.

"Our intent is to have oversight over how the collection is maintained, of the staffing, of how items are treated to make sure they are treated properly and to make sure donors' wishes are honored," McCaffrey said.

Even if the group wins the suit, she said it does not intend to pack up the collection and haul it away. The library and its collection, she said, was "created to be on the grounds of the Alamo."

"That's how we would like to see it remain," she said. "We simply want to see it remain intact and cared for properly."