In Europe, archaeology is seen as a separate discipline, while in the US, it is thought as a branch of anthropology.
There is a reason for this, and it's not a pretty one: in Europe, archaeologists worked with material remains of past European societies- their own past, while in America archaeologists worked with Native American material remains- remains that they didn't consider their own legacy, but a part of other cultures that anthropology had to deal with.
Both history and archaeology try to explain human past. But history does that using written sources, and archaeology uses material sources.
When combined, they can give beautiful results, but it's often not the case: written and material sources sometimes contradict each other. So, which one is more reliable? There's no clear answer to this. On one hand, humans can lie when writing about a subject, while material remains never lie. On the other hand, „reading“ a material remain is much more difficult than reading a written material.
Prehistory makes 99% of human history
That was the time when there was no writing, so the only way to study these periods is through archaeology.
Archaeology often relies on cross-disciplinary research.
It uses history (written sources), as well as socio-cultural anthropology, art history, classics, ethnology and linguistics. But it also uses sciences, such as chemistry, statistics, paleontology and physical anthropology.