| Treaty between Great Britain, France, Russia, and Greece, respecting theUnion of the Ionian Islands to the Kingdom of Greece. | |
|---|---|
 1914 postal card for the fiftieth anniversary of the union of the Ionian Islands with Greece | |
| Type | Multilateral treaty |
| Context | Union of the Ionian Islands with Greece |
| Drafted | 23 September 1863 (1863-09-23) |
| Signed | 29 March 1864 (1864-03-29) |
| Location | London,England |
| Effective | 21 May 1864 (1864-05-21) |
| Negotiators | |
| Original signatories | |
| Ratifiers | |
TheTreaty of London in 1864 resulted in the United Kingdom ceding theUnited States of the Ionian Islands toGreece. Britain had held anamical protectorate over the islands since the 1815Treaty of Paris.
The federated United States of the Ionian Islands included seven islands off the coasts ofEpirus and thePeloponnese, that hadremained inVenetian hands until 1797 and escapedOttoman rule. Of the seven, six lay in theIonian Sea, off the western coast of the Greek mainland. These six states wereCorfù (Kerkyra),Ithaca(Ithaki),Paxò(paxoi/paxos),Cephalonia,Zante (Zakynthos) andSanta Maura (Lefkas).Cerigo (Kythera) was also a state of the federation, although it is situated southeast of the Peloponnese.
Ever since Greece theGreek War of Independence against the Ottoman Empire, the people of the Ionian Islands had pressed for union, orenosis, with Greece. At a meeting of the British Cabinet in 1862,Foreign SecretaryHenry John Temple, 3rd Viscount Palmerston decided to cede the islands to Greece. This policy was also favoured byQueen Victoria.
The decision to cede the islands was also influenced by the accession to the Greek throne of the Danish princeGeorge, a committed Anglophile. Indeed, in areferendum in November 1862, the Greeks had elected Queen Victoria's second son,Prince Alfred, as their king, partly in the hope of receiving the Ionian Islands.
After long negotiations with Greece, the Treaty of London was signed by Greek delegateCharilaos Trikoupis on 29 March 1864. On 21 May 1864 the British departed and the Ionian Islands became three provinces of the Kingdom of Greece, although Britain retained use of the port on Corfu.
This can be seen as the first example of voluntarydecolonization by Britain. For Greece, the incorporation of the Ionian Islands was the first of several territorial increases to 1947.
