-The increase of immigrants
-The aftermaths of WWI
I really don't know if what I said is correct, but I just thought of it as of what happened before 1920
On June 1914 group of six Austrians gather to assassinate Archduck but failed. The reaction among the people in Australia was mild and indifferent. This was the trigger to World War I. Russia declared mobilization in a month. Germany declare war on Russia a month later in August. While Japan entered the war on the side of allies on 23August. France began full mobilization on 1 August and on 3 August Germany declared war on France. Belgium and Luxembourg dead soon without struggle.
Answer:
Traders from Europe went to West Africa and offered cloth, rum, salt, and other goods in exchange for slaves. Many Africans became wealthy by trading slaves for goods like these. In addition to these goods, the European traders also offered to trade guns for slaves.
European trading had a transforming impact on Africa. Europeans poured into Africa enormous volumes of commerce, the whole range of European manufactured goods and hardware, notably firearms, luxury goods (especially alcohol) and transhipped items from Asia (particularly textiles).
