The University of Montana is mourning the death of former President George Dennison at age 81.

Dennison was the longest-serving president in the school's history, from 1990 to 2010. Dennison's family said he died after a long battle with non-Hodgkin lymphoma. Dennison passed away early Tuesday morning surrounded by his family, and a celebration of his life will be held in May with details to be released at a later date.

Commissioner of Higher Education Clayton Christian remembers Dennison as a strong, dedicated leader, and describes some of the qualities that Dennison displayed that he might look for as the search for a new president is underway.

"He was truly an inspirational leader for that campus," Christian said. "He was inclusive at many levels and would make good decisions and see that they were executed on well. He would certainly let you know his opinion which we always appreciated, but was always a man of respect who worked so well with the Board of Regents. Civil discourse was something that he was always good at and it served the institution well and he made his mark as a leader."

Interim President Sheila Stearns was Commissioner of Higher Education during Dennison's tenure at UM, but also remembers her time with him on staff at UM.

"I first worked for his the day he stepped on campus," Stearns said. "I was a vice president in 1990, and we worked together, traveled together, and I remember in mid-July driving with him on his first visit to Helena and cautioning him about speeding along certain spots."

Stearns recalls Dennison as an intellectual giant.

"Those involved in higher education know that we've lost a real giant in the field of Montana education, as well as leadership," she said. "I also think a lot of people around the country are grieving today over a real extraordinary leader, and he will be missed all over, and not just in Montana."

Former President Royce Engstrom spoke to KGVO News while visiting family in Cincinnati.

"It's certainly a sad day for the University of Montana, the state of Montana, and really, for all of higher education in our country," Engstrom said. "George was a real standout in terms of leadership for higher education, highly respected and highly regarded by everyone around the nation. We're clearly going to miss him. He did such a fine job for the university and he always had the students in mind in terms of his decisions and the direction for the University of Montana."

KGVO reached out for former UM Vice President Jim Foley, who worked closely with Dennison for many years.

"A lifetime in education taught George Dennison that the real beauty of life was that odds were always meant to be defied," Foley began. "The public George Dennison came to higher education because he was always curious, a good student, and stayed because it was always fun and he changed students' lives for the better. In the 20 years he was President of the University of Montana, he clearly brought the flagship institution into the 21st century with more students, more graduates, more new academic programs than ever before in the long history of the University of Montana."

It is said that more students graduated from the University of Montana during Dennison's tenure than in the school's entire history prior to his presidency.