When protesters took up camp along the Dakota Access Pipeline route, they claimed they were taking back Land that was given to them in accordance with the 1851 Fort Laramie Treaty.

That treaty was one of several treaties that began to establish where current plains reservations are today.

The 1851 treaty established Sioux territories from the Heart River just south of Mandan, well into Montana, Wyoming and Nebraska. In fact, the treaty included almost all of South Dakota west of the Missouri river.

Protesters have used that as justification for setting up the camp and roadblocks that led to Thursday's confrontation.

Another treaty at Fort Laramie in 1868 moved the northern border of Indian Country to near what's now the North Dakota, South Dakota Border.

However, Tom Disselhorst a former federal Indian law professor at United Tribes Technical College, says that did not cancel out the lands given in 1851.

"That 1851 Treaty was never cancled. Nobody ever said it was no good anymore and so in that respect, since it's been ratified, it was established as the lands the United States took under the Indian Claims Commission," said Disselhort.

The ICC said in 1974 the United State took more than $17 million worth of Sioux land. Disselhort says even though Congress appropriated for it, the tribes never accepted the money.