In 1848, gold was discovered in California, which would lead to changes
Bands
Smaller groups within a tribe, could be several hundred people or just 20 or 30 people
Chiefs
They were the leaders of Plains Indian society, always men
Each tribe could have many chiefs - a war chief, a spiritual chief and a chief who led negotiations
Chiefs were valued for their wisdom, leadership, spiritual powers or skill as warriors or hunters
Chiefs were rarely chiefs for life, they came and went as their skills emerged and faded
Band chiefs and elders
They made up the tribe's council when the tribe came together
The council could declare war on another tribe, or negotiate a peace treaty
Everyone could give their opinion in the council and was listened to
No decision was made until everyone at the council had agreed to it
Warrior brotherhoods
Young men joined after proving their bravery and skill in fighting with other tribes
They trained young men in fighting skills and taught them about the tribe's beliefs and values
Warrior brotherhoods were not under the command of the tribal council in many tribes
Leading men from the brotherhoods were invited to join a guard unit for the whole tribe
Last Child Society
A warrior brotherhood started by Crazy Horse, made up only of youngest sons who would be the bravest and most daring
Women's role
They were responsible for feeding and clothing their families, processing buffalo hides and meat, and turning them into products that could be traded
Women's roles were respected very highly as everyone needed to perform their specialised role with great skill if the tribe was to survive
Challenges the Plains Indians faced included hot summers, extremely cold winters, dry conditions with little surface water, and lightning flashes that could cause great fires
Crazy Horse's thinking was that the youngest son always tries to impress his brothers and sisters and so the 'last child' would be the bravest and most daring
Women could not be chiefs and a successful man could have more than one wife in Plains Indian society
Women were responsible for feeding and clothing their families and for their family's possessions
Women were also responsible for processing buffalo hides and meat, turning them into products that could be traded
Women's roles were respected very highly
Both men and women had set roles that could not change
This was because everyone needed to perform their specialised role with great skill if the tribe was to survive
Challenges faced by the Plains Indians
Hot summers
Extremely cold winters
Dry, with little surface water (streams or rivers)
When rain comes, it is often in thunderstorms
Lightning flashes could cause great fires, which swept across the Plains, burning the dry grass
Strong winds made the fires worse
The lives of the Plains Indians depended on the buffalo
White Americans believed the only way to hold onto the land was to fill it with loyal, white Americans
This idea was called Manifest Destiny
In 1837, there was an economic crisis in the East and the South of the USA, which lasted until the mid-1840s
Many banks collapsed, people lost their savings, businesses failed and people lost their jobs
In some areas, unemployment was as high as 25%
Those who still had a job faced wage cuts of as much as 40%
Traders and fur-trappers had been travelling to Oregon (on the USA's Pacific coast) for many years and they passed back news of the rich farming land west of the Rocky Mountains
The sea route to Oregon was expensive – it cost at least $300, when a farm labourer could expect to earn $11 a month
It also took as long as a year to make the trip round South America and up the west coast of the USA
Migrants needed an overland route that wagons could travel on so they could transport everything they needed to set up a new life in the West
The high mountain ranges of the Rockies and Sierra Nevada formed an enormous barrier
A way through the mountains was needed before migration to Oregon could begin
The key part of the route, the South Pass in the Rocky Mountains, was first publicised by an explorer called Jedidiah Smith in 1825
Fur trappers started to use the route, digging out a path through gullies, clearing scrub vegetation and finding the best spots to cross rivers
By 1869, when the Oregon Trail was replaced as the main way of travelling west by the First Transcontinental Railroad, 400,000 people had migrated along the Oregon Trail
The first migrants to travel the Oregon Trail with a covered wagon reached their destination in 1836
They were two married couples, Narcissa and Marcus Whitman and Henry and Eliza Spalding
They were all missionaries who travelled to Oregon to convert American Indian tribes to Christianity
Their success established the Oregon Trail as a route for migrants
In 1840, the Walker family (including five children) completed the Trail
In 1841, a party of 60 people made the trip, 100 people in 1842 and 900 people in 1843
This proved that large numbers of people could make the journey
The 1843 trip was called the 'Great Emigration' and was led by Marcus Whitman