DOVER AIR FORCE BASE, Del. -- The Mexican-American War and the Battle for Monterrey are, in part, the reason Tennessee is called the "Volunteer State."The state's nickname is derived from the outpouring of support during the War of 1812, and again in 1846 when the U.S. declared war against Mexico. During that conflict, a reported 30,000 Tennesseans volunteered and marched against Mexico after the nation had requested just 10 percent of that robust force.On Wednesday, Sept. 28, approximately 170 years after the war, as many as 13 skeletal remains were returned to U.S. soil and honored during a solemn transfer at Dover Air Force Base in Delaware.The movement of the remains, believed to be members of the Tennessee militia who died in the Battle of Monterrey in 1846, was the culmination of more than three years of diplomatic negotiation, sparked by a professor of forensic science at Middle Tennessee State University, according to Andrew Oppmann, the university's spokesman.The remains, transported aboard an Army C-12 aircraft, were carried to an awaiting vehicle by the Army Old Guard ceremonial team, under the watchful gaze of senior military, university and government leaders.A delegation of MTSU officials flew in to witness the dignified transfer of the remains and meet with experts at the Armed Forces Medical Examiner System (AFMES) to establish a collaboration geared at discovering more details about them.Army Colonel Louis Finelli, AFMES director, said it was too early to speculate how long the process would take. His team plans to work closely with MTSU's staff in studying the skeletons."Given the age of the remains, we can do everything in our power, but without accurate references and accurate family genealogy, we may not be able to put a name to them," Finelli said. "We should hopefully be able to at least individualize these remains."During the transfer, U.S. Rep. Diane Black, of Tennessee, stood with the official party of senior military, university and government representatives. Her office first became aware of the remains in 2011, and she and other members of Tennessee's congressional delegation worked with Mexican officials to retrieve them."It had taken six years to bring these brave Soldiers home," she said, during a break in the otherwise constant drizzle. "We have been in ongoing negotiations with the Mexican government and we have finally returned our fallen … heroes back to American soil."Rep. Black lives about seven miles from a cemetery where Mexican-American War dead are buried. She said if the bones are indeed determined to be Tennessee militia volunteers, "We would love to see their remains buried in that cemetery."Oppmann described the history surrounding the Mexican-American War, which ended in 1848 as nothing less than fascinating."In September 1846, American forces caught the Mexican army in retreat at the city of Monterrey in northern Mexico," he said. "[Monterrey] is referenced as 'a Perfect Gibraltar' for its formidable defenses."Oppmann went on to describe a frontal attack in which U.S. commander Zachary Taylor sent regular soldiers and Texas militia as the main attack force to the western sector. At the same time, a regiment of regulars led by West Point officers Ulysses S. Grant and Braxton Bragg, along with volunteer regiments from Mississippi and Tennessee, attacked the northeastern sector.With a specific nod to the militia of his home state, Oppmann noted that the unfortunate distinction of the "Bloody First" went to a Tennessean regiment that suffered staggering losses."Fourteen percent of all forces engaged were killed or wounded [about 394] men, representing one of the bloodiest days in West Point history as 11 former cadets fell in action," Oppmann said.He also noted that Mexican war records indicate the dead were buried in "hastily covered mounds" along the roadside."Historical evidence strongly indicates that these burials are likely those of Tennesseans," according to Oppmann.Dr. Hugh Berryman, a MTSU forensic anthropologist and professor, leads a team of 22 scientists that will work closely with AFMES to shed light on the remains."They were in a part of the battle that had a high number of Tennesseans that died," said Berryman. "This is important for a number of different reasons."But perhaps the most important of which, Berryman said, is how interwoven the Mexican-American War is with the very identity of Tennessee."We're the 'Volunteer State,'" he said. "That name was given to us by the War of 1812, and this war, in 1846."-----HISTORICAL NOTE:In 1848, the Treaty of Guadalupe Hidalgo ended the war and demanded the Mexican Cession of territories of Alta California and Santa Fe de Nuevo Mexico to the United States. The U.S. agreed to pay $15 million to pay the physical damage of war. In addition, the U.S. assumed approximately $3.25 million of debt owed by the Mexican government to U.S. citizens. Mexico recognized the loss of Texas and thereafter cited the Rio Grande as its national border with the U.S.