people to govern the new place. Those
places are often called colonies as well.
In the 1800s, for example, European
countries seized control of most of
Africa. In most cases only a small number
of Europeans went to the colonies in
Africa. They oversaw the government of
the colonies. They also set up businesses
and controlled trade. Sometimes the
European colonizers forced the Africans
to work for them.
Effects of Empires
Imperialism has had a great influence on
world history. It has led to the discovery
and development of new lands. Imperial
powers have built useful things such as
roads, schools, and hospitals. Imperialism
has also spread knowledge and culture.
In many places that were once
colonies, the people still speak the language
of the colonizers. The religions of
colonial powers are also common in
former colonies.
Imperialism has also had many negative
effects. Imperial powers killed many
native people in wars of conquest. They
made other native people work for low
wages or as slaves. They also often forced
the people to give up their traditional
way of life.
History
The Phoenicians were among the earliest
colonizers. About 3,000 years ago they
set up trading posts along the eastern
coast of the Mediterranean Sea, in
North Africa, Anatolia (now Turkey),
and Cyprus. Later the Assyrians, the
Persians, the Greeks, and the Romans
had empires in the region. The Roman
Empire reached all the way from Britain
to Egypt.
Imperialism also happened in Asia. The
first empire in India was established in
the 300s BC. In China the Qin Dynasty
created the first empire in 221 BC.
After the fall of the Roman Empire in
the AD 400s, no European country was
Great Britain ruled land all over the world
from about the 1600s to the 1900s. A map
shows the huge size of the British Empire in
the late 1800s. The British lands are shown
in orange.
The Romans built Hadrian’s Wall across
Great Britain in ancient times. It included a
long stone wall and forts to keep invaders
out of the Roman colony in Britain.
BRITANNICA STUDENT ENCYCLOPEDIA Empire 131
strong enough to establish colonies.
Between the 600s and the 1200s Arabs
built up an empire in western Asia,
North Africa, and Spain. They spread
their religion, Islam, to the places they
conquered.
In the late 1400s European explorers
first crossed the Atlantic Ocean to the
Americas. That began a great age of
exploration. Soon European countries
began claiming land in the Americas,
India, and the East Indies. England,
France, Spain, Portugal, and the Netherlands
had many colonies.
Most colonies in North and South
America gained freedom between 1776
and 1826. But at the same time European
countries started building empires
in Africa. In the 1880s European powers
divided up almost all of Africa between
themselves.
In the late 1800s and early 1900s the
United States and Japan became colonial
powers. The United States took control
of islands in the Caribbean Sea and the
Pacific Ocean. Japan conquered lands in
East Asia. Imperialism by Japan, Italy,
and Germany in the 1930s led toWorld
War II. After the war the Soviet Union
built an empire in eastern Europe.
The large empires of the past no longer
exist. Between 1945 and 1990 about
100 colonies gained their freedom.
Sometimes this happened peacefully,
with the colonial power stepping aside.
Other times the people of the colonies
fought for independence.
#More to explore
Africa • Americas, Exploration and
Settlement of the • Colony • Greece,
Ancient • Phoenician • Rome, Ancient
Encephalitis
Encephalitis is an inflammation, or
swelling, of the brain. It is often a mild
illness, but serious cases can cause brain
damage.
Particles called viruses or such tiny living
things as bacteria and parasites can cause
encephalitis. So can harmful chemicals.
Viruses are the most common cause.
The viruses that cause chicken pox,
mumps, and measles can turn into
encephalitis. These viruses spread from
person to person. Mosquitoes and other
biting insects also spread viruses. Some
Great Britain gave Hong Kong
back to China in 1997. Hong
Kong was the last major colony
of the British Empire. Members
of the Chinese military attend a
ceremony marking the peaceful
return of the colony.
132 Encephalitis BRITANNICA STUDENT ENCYCLOPEDIA
of these viruses, such as West Nile virus,
can cause encephalitis.
Encephalitis has a wide range of symptoms,
or signs. These include fever,
headache, tiredness, a stiff neck, and
vomiting. In the most severe cases
people may fall into a coma. A coma is a
deep, heavy sleep. Recovery in severe
cases can take weeks. There may be
damage to the brain that cannot be
fixed.
Doctors use medicines to fight the
causes of encephalitis and to ease its
symptoms. The best way to prevent
encephalitis is to stop the spread of the
things that cause it.Washing hands
helps to kill viruses and bacteria. Insect
repellent helps to keep insects from biting.
Vaccines prevent many illnesses that
can cause encephalitis. Vaccines are substances
given to healthy people that help
the body fight disease.
#More to explore
Brain • Virus
Endangered
Species
An endangered species is any type of
