A Congressional Medal of Honor awarded to Joshua Chamberlain for his role in the Battle of Gettysburg was discovered in the back of a book bought at a church fundraising sale.

The medal, which was found in Duxbury, Mass., has been verified as authentic after being sent anonymously in July to the Pejepscot Historical Society in Brunswick, Maine.  At first, historians were skeptical since they believed the original Medal of Honor was safely displayed at Bowdoin College, the Times Record reports.

“All of the experts we’ve consulted believe it to be authentic, and we are tremendously honored to return the medal to Chamberlain’s home in Brunswick,” Pejepscot Historical Society Director Jennifer Blanchard said.

It turns out Chamberlain was awarded two medals for his Civil War service, one in 1896, and another in 1904 -- the second one is held at Bowdoin.

Chamberlain was bestowed the Medal of Honor on Aug. 11, 1893, by U.S. President Grover Cleveland, in recognition for his heroism at Little Round Top during the Battle of Gettysburg 30 years earlier. After his death in 1914, his medal was passed on to his descendants. When his granddaughter, Rosamond Allen, died in 2000, her estate was donated to the First Parish Church of Duxbury.

An anonymous man from Massachusetts who bought several books at a church sale found the medal and tried to return it to its original Maine home twice – the first time the envelope was misaddressed.

“There is photographic evidence that Chamberlain was very proud of the medal, that he wore it quite often,” Blanchard said about the 120- year-old medal.

After the medal was verified by the Smithsonian, Library of Congress, Maine State Museum, and the Army's Awards and Decorations branch, the historical society accepted the donation following the donor’s wish that it will be “in honor of all veterans.”

"We are tremendously honored to return the medal to Chamberlain’s home in Brunswick. The timing couldn’t be better, since the medal was awarded for Chamberlain’s distinguished service in the Battle of Gettysburg, whose 150th anniversary we mark in 2013," Blanchard said in a statement.

The Defense of Little Round Top on July 2, 1863, is seen as “the most famous counterattack of the Civil War,” where Union Colonel Joshua Chamberlain led a charge against the Confederate army and was credited with saving Major General George Gordon Meade’s Army of the Potomac and winning the Battle of Gettysburg. Chamberlain was awarded the medal for displaying “distinguished gallantry” in the battle.

Chamberlain, who was 34-years-old at the time, was a highly cultured professor of modern languages at Bowdoin. A native of Brewer, Maine, Chamberlain joined the Union army July 1862 and was given command of the 20th Maine Infantry Regiment. After the war, he served four years as governor.

“Chamberlain seemed to have been blessed with both good timing and luck,” James R. Brann, of the Civil War Trust, writes about the battle. “He not only had made the right command decisions but also had managed to survive when by all rights he should have been dead.”