Military campaigns accompanied the very rise of the Aztec civilization. Aztec tribal leaders undertook a series of campaigns to strengthen their influence. Many tribes were turned into vassals who paid tribute to them. Aztec religious beliefs led to many violent deaths. They believed that the gods would bring doom if they did not often sacrifice people, and for this purpose, they often used prisoners of war and members of smaller tribal communities.
Throughout history, they have served as a mercenary army to other cities and states, and over time they have become so strong that they have attacked their masters and become absolute rulers. The state's very structure was militaristic and implied constant expansion, which led to a large number of victims. Many conquered peoples had to pay high taxes, and the Aztecs kept proper records of it. All these factors are proof that the Aztecs were a violent civilization.
<em>Biostratigraphy </em>is the method that is used to provide an estimate of age for this layer and this species. Biostratigraphy is a branch of stratigraphy. It focuses on assigning relative ages to rocks to similar stratigraphic layers that may be located hundreds of kilometers away by using the fossils contained in the stratus.
