Classical Athens, for example, forced weaker states into the Delian League and in some cases imposed democratic governments on them.
[citation needed] The number of tributary or vassal states varied over time but most notable were the Khanate of Crimea, Wallachia, Moldavia, Transylvania, the Sharifate of Mecca, and the Sultanate of Aceh.
[citation needed] Austria-Hungary tried to make Serbia a client state in order to form a Christian opposition to the Ottoman Empire, but after the 1903 May Coup, Serbia came under the influence of Russia, which was forming a pan-Eastern Orthodox opposition to the Latin Christianity represented by the Austro-Hungarian Empire.
At the time, Great Britain and Austria-Hungary both considered Serbia as a client state controlled by Russia.
But in both cases, the economic and military reality did not amount to full independence, but a status where the local rulers were British clients.
Other instances include Africa (e.g. Northern Nigeria under Lord Lugard), and the Unfederated Malay States; the policy of indirect rule.
[17][18][19] In the late 19th century, the Empire of Japan gradually reduced Joseon Korea's status to that of a client state.