Norse reached Newfoundland around 1000; Spain and Portugal split the world in 1494
Large-scale European colonization of the Americas ran mainly from the late fifteenth century into the early nineteenth. Norse settlers had already planted Greenland and a brief foothold near Newfoundland's northern tip around 1000 CE, centuries before Columbus sailed and Spain built its empire.
The Norse came first. Their Greenland colony, founded in the late tenth century, survived until the mid-1400s, with assemblies meeting at Brattahlíð and a bishop based at Garðar. In 1960 archaeologists uncovered a Norse site at L'Anse aux Meadows in Newfoundland, and carbon-dated to roughly 990 to 1050. It remains the only widely accepted proof of transatlantic contact before Columbus, became a UNESCO World Heritage Site in 1978, and may be linked to Leif Erikson's attempted colony of Vinland. His brother is said to have made the first contact with local people, killing eight of them and then fighting off an attack on the Norse ships.
The later wave had other roots. In the early fifteenth century Europe was still absorbed by internal wars and recovering from the Black Death, so its coming rise was hard to predict. Ottoman control of the routes to Asia pushed western monarchs to look for alternatives, and Columbus reached the Americas by accident. The Treaty of Tordesillas in 1494 divided non-Christian lands between Portugal in the east and Spain in the west, which is how Portugal came to hold Brazil and Spain the Philippines. Santo Domingo, founded by Columbus in 1496, is regarded as the oldest continuously inhabited European settlement in the Americas.
Others soon followed. From the 1530s English and French colonists moved into the northeast; within a century Sweden had New Sweden and the Dutch New Netherland, and Denmark-Norway joined them in the Caribbean. By the 1700s Denmark-Norway had revived the old Greenland colonies and Russia was claiming the Pacific coast from Alaska toward California. Spain, Portugal, Britain, France, Russia, the Netherlands, Denmark and Sweden all took part.
For Indigenous peoples the consequences were catastrophic: displacement, enslavement and genocide, alongside wars against settlers and against neighbours armed with European weapons. Conflict with Native nations continued into the 1800s, including after independence, as the United States pursued Manifest Destiny and Indian removal. Some areas, such as California, Patagonia and the northern Great Plains, saw little colonisation until that century. Many of today's languages, religions and borders across the hemisphere descend from this era.
Source: European colonization of the Americas