The British Band was a mixed-nation group of Native Americans commanded by the Sauk leader Black Hawk, which fought against Illinois and Michigan Territory militias during the 1832 Black Hawk War. The band was composed of about 1,500 men, women, and children from the Sauk, Meskwaki, Fox, Kickapoo, Potawatomi, Ho-Chunk, and Ottawa nations; about 500 of that number were warriors. Black Hawk had an alliance with the British that dated from the War of 1812, giving them their colloquial name. The band crossed the Mississippi River from Iowa into Illinois in an attempt to reclaim their homeland and in violation of several treaties.

Sauk warrior Black Hawk, the leader of a band of Sauks near Rock Island at Saukenuk, was always in opposition to ceding Native American lands to white settlers and their governments. Black Hawk supported the invalidity of the Treaty of St. Louis (1804) of both the Sauk and Fox nations negotiated with the then Indiana Territory Governor William Henry Harrison. The treaty ceded territory, including Black Hawk's birthplace Saukenuk, to the United States. The Sauk are a consensus decision making society. Their representatives exceeded the authorization of merely taking under consideration what terms the United States government might put forth, bring them back to reach a consensus and then return with their treaty terms. The lack of the tribe discussing the treaty prior to being made official made it invalid by Black Hawk and other members of the tribe. The representatives never had the tribal authorization to unilaterally cede its lands. During the War of 1812 between the United Kingdom and the United States, Colonel Robert Dickson, an English fur trader, amassed a sizable force of Native Americans at Green Bay to assist the British in operations around the Great Lakes. Most of the warriors Dickson assembled were from the Potawatomi, Ho-Chunk, Kickapoo and Ottawa tribes. Dickson bestowed the rank of brevet Brigadier General on Black Hawk. He was given command of all Native Americans gathered at Green Bay, including the 200 Sauk warriors under Black Hawk's control. Black Hawk was then presented with a silk flag, a medal, and a written certificate of good behavior and alliance with the British. The certificate would be found 20 years later, after the Battle of Bad Axe, carefully preserved along with a flag similar to the one Dickson gave to Black Hawk. During the 1812 war, Black Hawk and his warriors fought in several engagements with Henry Procter on the borders of Lake Erie. He returned home to Saukenuk to find his rival Keokuk had become the tribe's war chief. After the war ended, Black Hawk signed a peace treaty in May 1816 that re-affirmed the treaty of 1804, a provision Black Hawk later protested ignorance of. Despite opposition by Keokuk and the US authorities, Black Hawk's band returned to Saukenuk in 1830 following their winter hunt. A year later they returned again, and Illinois Governor John Reynolds proclaimed it an "invasion of the state." Responding to Illinois Governor John Reynolds' call, General Edmund Pendleton Gaines brought his federal troops from St. Louis, Missouri to Saukenuk to insist on Black Hawk's immediate departure. Black Hawk left but soon returned to the west side of the Mississippi, threatened by Gaines' troops and an additional 1,400 militia called up by Reynolds on 25 June 1831. On 30 June, Black Hawk and the chiefs of the British Band were forced to sign a surrender agreement in which they promised to remain west of the Mississippi. At the end of 1831, stories spread throughout the settlements of the Upper Mississippi River Valley that the British planned to aid Black Hawk in the event of a war with the white settlers. According to U.S. Indian Agent Felix St. Vrain, a known ne'er-do-well named Billy Caldwell had delivered a message to the Sauk which reported the alleged British intentions. The New Galenian of Galena reported that Black Hawk's band would receive aid and ammunition from the British, and the tale was widely believed. The militia commander at Fort Armstrong, Major John Bliss, informed General Henry Atkinson of the rumor, and said a follower of Keokuk had reported to him that Black Hawk and Neapope were holding talks with bands of Potawatomi, Kickapoo, and Ho-Chunk. The talks mentioned the promises of the British, as well as word that the French Canadians intended to assist them. These events, combined with Black Hawk's 1812 alliance with the British, and occasional visits to Canada, attributed to his 1832 band becoming known by the moniker British Band. The term British Band was used frequently by American, Sauk, and Fox observers alike and served to distinguish Black Hawk's group from the rest of the tribes. When Black Hawk's Band crossed the Mississippi River from Iowa in April 1832 to return to their homeland in the Rock River Valley, it was under a British flag. Potawatomi Chief Shabbona stated it was the same flag that had been given on a visit to the British in Malden, Ontario, Canada. Observers at the time, from George Davenport, to St. Vrain, were certain that Black Hawk's intentions were to wage war against the United States. Historians generally believe that a more decisive action by General Atkinson, charged with prosecuting the war, in stopping Black Hawk's Band from moving up the Rock River may have prevented the war. Zachary Taylor made similar observations shortly after the war ended. In response to Black Hawk and his band's movements, Governor Reynolds issued a proclamation on 16 April, mustering five brigades of volunteers to form at Beardstown and to head north to force Black Hawk out of Illinois. Although one-third of all federal troops from the United States Army were eventually involved in the conflict, the 9,000 soldiers from the Illinois Militia provided the majority of U.S. combatants. The first named confrontation of the Black Hawk War occurred on 14 May 1832 and resulted in an unexpected victory for Black Hawk's band of Sauk and Fox warriors over the disorganized militia under the command of Isaiah Stillman. Soon after the Battle of Stillman's Run, at present-day Stillman Valley, the exaggerated claim that 2,000 "bloodthirsty warriors ... sweeping all northern Illinois with the bosom of destruction" sent shock waves of terror through the region. After this initial skirmish, Black Hawk led many of the civilians in his band to the Michigan Territory. On 19 May, the militia traveled up the Rock River trailing and searching for Black Hawk and his band. Several small skirmishes and massacres ensued over the next month in northern Illinois and present-day southern Wisconsin before the militia was able to regain public confidence in battles at Horseshoe Bend and Waddams Grove. CANNOTANSWERAnswer this question using a quote from the following article:

Why did black hawk support teh invalidity  of the treaty of St. Louis?

The treaty ceded territory, including Black Hawk's birthplace Saukenuk, to the United States. The Sauk are a consensus decision making society.