Imperialism was a mid-19th-century invention. The period after 1870 in world history has come to be known as the age of Imperialism.
In the early part of the 19th century, old colonial empires built up by European nations were crumbling to pieces on all sides. Between 1763 and 1825 all empires suffered serious loss, with the exception of Britain.
Great Britain had lost 13 colonies of America in 1783, Early in the 19th century, the Spanish colonies in America likewise revolted, Brazil established its independence from Portugal in 1822, With these developments of colonies declaring independence, the colonial centres lost faith in the value of colonies.
Factors in the rise of Imperialism
Search of Raw Materials: The Requirements of modern industries led to enormously increased demands for the raw material of tropical countries. This enhanced the value of colonies as a source of supply of materials. Africa and Asia offered many of the raw materials needed by the multiplying factories of Europe such as cotton, silk, rubber, vegetable oils, and minerals.
Search for Markets: Up to 1870, British manufacturers of textiles, machinery, and hardware found good markets in other European countries. After 1870, Germany, France, Belgium, and other nations were able to satisfy their own home markets which they began to protect against imports from Britain by productive tariff barriers. They even began to produce a surplus for which they also wanted markets abroad. With the increasing saturation of European markets all started looking for more open overseas markets. They found their governments responsive to national needs undertaking political conquests of underdeveloped territories, The vast underdeveloped areas of Africa and Asia offered the most inviting opportunities provided they should be made safe for investment by conquering them. The international anarchy prevailing at that time gave an impetus to the general race for colonies. In some countries like Russia and Italy, Political considerations predominated. Neither Italy nor Russia has a surplus of manufactures or capital to export, yet both of them joined in the race for colonies.
Political Factors: Politically as some of the nations with far-flung Empires needed naval bases and coaling stations. The temper of the age grew more materialistic.The European nations came to realise that the colonies might act as military bases. There was also a belief that the acquisition of colonies reflected the glory of the mother country.
National Pride: Countries such as Italy and Germany had the spirit and hunger for national pride and this supplied a very strong incentive to colonial expansion. In the exuberance of national pride, they wanted to establish their status as the world powers. The huge colonial Empire of Britain had set a standard with the entry of Italy and Germany from the last quarter of the 19th century. The competition for overseas possessions became keener.
Expanding population: Economic distress and periodical recurrence of unemployment led millions of Europeans to migrate from Europe to find new homes and careers abroad.
Desire to Spread Christianity: There was a desire for all the Christian nations to spread their faith in all parts of the world, Christian missionaries undoubtedly had a strong desire to raise the civilization of backward people and to teach them principles of health and sanitation, but unfortunately their missionary activities were neutralized by the shameless immorality and heartless cruelty exhibited by European officials and merchants in their dealings with the subject people. It is rightly said that the assertion of high principles by statesmen and imperialists was a pretext for acquiring colonies. Sentimental moral and altruistic considerations were convenient justifications of Imperialism.
Also, read about Regionalism in India