Collectors are planning an all-out assault on Gettysburg, Pennsylvania, this weekend to bid on millions of dollars worth of items from the Civil War.The victors will walk away with Lt. Col. George Armstrong Custer's frayed battle flag and a diamond-adorned sword that was presented to Gen. Ulysses S. Grant, who later served as president. Each is estimated to bring winning bids in the range of US$2 million (euro1.5 million).The two items are among more than 750 that will be put up Sunday and Monday in Gettysburg -- site of the 1863 tide-turning Civil War battle -- by Heritage Auction Galleries of Dallas. Online and phone bidders will also participate.The silk, swallow-tailed flag was made by Custer's wife, Elizabeth, and carried into battle during the closing days of the all-American conflict. The banner, which features crossed cavalry sabers, was at Custer's side at Appomattox Courthouse, Virginia, when Gen. Robert E. Lee surrendered Confederate forces to Grant.The flag was left at Custer's headquarters at Fort Abraham Lincoln, Dakota Territory, in 1876 when Custer and his men were wiped out at Little Big Horn by Lakota and Northern Cheyenne warriors.Custer's flag stayed within his family until 1956, when it was acquired by Dr. Lawrence A. Frost, who kept it until 1990. Elizabeth Lawrence owned the flag until 2003, when it went to the collection of Thomas Minckler of New York City.Grant's sword was presented by citizens of Kentucky in 1864 to honor his promotion to General-in-Chief of all Union forces. The silver and gold sword contains a 28-diamond monogram and is covered with intricate designs, including engraved battle scenes on its 33-inch (84-centimeter) blade. The sword has belonged to the Donald Tharpe Collection of American History since 1989. It remained in Grant's family until the 1960s, when it was acquired by collector Jay Altmeyer.Gary Hendershott, Heritage's director of Civil War auctions, sees the two showcase items as equally significant."There's more than military history, it's really American history. The Custer flag has so much romance wrapped up in it, it was made by his wife," Hendershott said.The sword, he said, may be the finest from the Civil War period. "It's really a hallmark of American silversmith craftsmanship." He noted that bidders in France recently paid more than US$6.5 million (euro4.84 million) for a gold-encrusted sword once owned by Napoleon.Other items in the wide-ranging auction include Confederate Col. John Thompson Brown's frock coat; a "Bonnie Blue" flag carried by the 3rd Texas State Cavalry; and an ornate saddle cloth that belonged to Union Maj. Gen. Philip Sheridan. Each is estimated to bring as much as US$120,000 (euro89,279).