They now believe that widespread epidemic disease, to which the natives had no prior exposure or resistance, was the primary cause of the massive population decline of the Native Americans.
The Native Population decreased for numerous reasons in New England. The first being diseases and illnesses. The Natives were not immune to diseases like the colonists were, so when the colonists came it heavily affected them and killed a lot of them. A famous one was the 1616 plague, this killed so many different Native tribes. Another reason for the decrease in American Indians were the wars. When the colonists came to the Americas, many of them clashed over land and got into wars. The Natives were outnumbered and did not have the tools or weapons to fight the colonists so many of them died, along with this, the ones who survived, many colonists turned to slavery and sold Natives (they were later replaced with African Americans, as they had stronger immune systems and more numbers). Many Natives ended up losing their land after the siding with the French during the French and Indian War, so when the French lost, the Indians ultimately lost all of their land to the colonists and had to move to reservations.
The Civil Rights Act of 1866 was the first United States federal law to define citizenship and affirm that all citizens are equally protected by the law.
