ROSEMONT, Ill. (AP) -- Rosemont Mayor Donald Stephens, who held the office for more than 51 years, died Wednesday following a year-and-a-half-long battle with stomach cancer, a city spokesman said. He was 79.

Stephens died in his sleep about 8 p.m. at his home in the Chicago suburb, spokesman Gary Mack said. Stephens had undergone extensive treatment for cancer, including chemotherapy and radiation, since his diagnosis, Mack said.

Stephens first was elected mayor of Rosemont in 1956, the same year the village was incorporated, according to its Web site. He was most recently re-elected in 2005 to a four-year term, Mack said. The spokesman did not have details Wednesday night about how the remainder of Stephens' term would be filled.

Rosemont had only 85 residents when Stephens became mayor more than a half-century ago, the Chicago Tribune reported. The tiny suburb near O'Hare International Airport flourished during his tenure as Stephens focused on large-scale projects -- building an entertainment center, a theater, and a convention center that bears his name.

"He took Rosemont from a tiny mud swamp to an incredible mecca of tourism in the hospitality industry," Mack said. The village Web site estimates its annual economic impact at about $248 million.

Stephens also had pushed to bring the Emerald Casino to Rosemont, which spent many years and millions of dollars on the proposed project. But the Illinois Gaming Board voted unanimously in December 2005 to revoke Emerald's gambling license, saying top company officials lied to regulators and let people with alleged ties to organized crime become investors.

In a summer 2005 hearing on the proposed casino's license, an FBI agent testified that Stephens had met with several organized crime figures about mob control of construction and operations contracts at the planned gambling hall. Stephens repeatedly denied allegations about any mob connections.

"The biggest problem that I've got is the allegations, and that's what they are, and the innuendoes and the accusations of mob influence, mob involvement in Rosemont, when there's no truth to it at all," he told the Tribune in October 2006.

Health problems kept Stephens from attending Rosemont's 50th anniversary celebration last year and the mayor recently had been visibly weakened by the cancer treatments, the (Arlington Heights) Daily Herald reported. When able, he presided over village board meetings wearing a hat due to hair loss and using a walker.

One of Stephens' sons, Bradley, who is a village trustee, has been serving as mayor pro tem at meetings his father was unable to attend, Mack said.

Stephens was born in Chicago on March 13, 1928. He is survived by his wife, Katherine; a daughter, Gail; and three sons, Donald, Mark and Bradley. Arrangements for services were pending Wednesday night.