In the midst of planning for a funeral and memorial service, family and colleagues of renowned Civil War professor William E. Gienapp remembered him yesterday as a gifted scholar, devoted teacher and avid Red Sox fan.

Gienapp, Harvard College professor and professor of history, died Wednesday morning at a hospital near his home in Lincoln, Mass., after suffering from cancer. He was 59.

The funeral service will be held Saturday at 12:30 p.m. in Memorial Church. The department will also sponsor a separate memorial service for Gienapp, said history department administrator Janet H. Hatch.

“Gienapp was so bright but yet so modest about his knowledge,” said McLean Professor of Ancient and Modern History Steven Ozment. “At times he would blossom and become the most witty person you could ever talk to.”

Gienapp’s wife, Erica, said that he developed his passion for history as an undergraduate at the University of California at Berkeley after taking a class on the Civil War taught by Ken Stamp. Up to that point he had been a physics and math major.

“He discovered his true love,” she said. “He fell in love with studying the Civil War and it really fueled his interest.”

Colleagues said that Gienapp’s greatest contribution to scholarship was his 1988 book, The Origins of the Republican Party, 1852-1856.

“He revived 19th century political history by working from both a quantitative and a narrative perspective. He was able to combine them both in his book on the origins of the Republican party,” said Warren Professor of American History David H. Donald.

William H. Moore, a professor of history at the University of Wyoming, where Gienapp taught before coming to Harvard in 1989, said Gienapp was an exemplary scholar.

“He was a marvelous, thorough researcher. He was as good a faculty member as ever came through the University of Wyoming,” said Moore, whose office was adjacent to Gienapp’s.

“His greatest book is on the origins of the Republican party, but his book on Abraham Lincoln [Abraham Lincoln and Civil War America: A Biography] will have a real impact on undergraduates,” Moore said. “I’ve already used it in class.”

William J. Rorabough, a professor of history at the University of Washington, said it was not simple for Gienapp to put together such a comprehensive work on Lincoln.

“No one has said so much about Lincoln in so few words. It’s a task that looks easy but is incredibly hard,” said Rorabough, who attended graduate school with Gienapp at the University of California at Berkeley.

Rorabough said that Gienapp may have been the foremost Civil War expert of his generation.

“He had an encyclopedic mind and he absorbed historiography in an incredible way,” he said. “He absorbed the vast literature on the Civil War and out of that his contribution was to synthesize and bring it together.”

Baird Professor of History Mark A. Kishlansky praised Gienapp’s dedication to undergraduate teaching and the courses he created.

“He was a great teacher who cared about undergrads,” Kishlansky said. “He built an absolutely terrific core course on the Civil War.”

David G. Blackbourn, Coolidge professor of history and the director of the Center for European Studies, said that, above all, Gienapp was a devoted teacher.

“He went out of his way, beyond the normal call of duty. His energies went into teaching. He was absolutely devoted to it,” he said.

Kishlansky said that he has fond memories of attending Red Sox games with Gienapp, who taught the popular history class, History 1653, “Baseball and American Society, 1840-Present.”

“He had the terrible misfortune of being a Red Sox fan,” he said. “I tried to help him through it.”

Gienapp is survived by his wife, Erica, two sons, William Gienapp ’01 and Jonathan E. Gienapp ’06, his mother, Jane and two brothers.