A "decree of the Eminent Senate of the Commonwealth of Ionian Islands" established the Ionian State Bank in 1839,
to finance trade between the Ionian Islands (a British protectorate), and Great Britain. This made the bank the oldest in Greece.
The bank received a 20-year grant of the exclusive privilege of issuing and circulating banknotes for the Ionian Islands. The bank soon changed its name to Ionian Bank (IB),
and initially only operated in the Ionian Islands, opening branches in Corfu, Zakynthos and Kefalonia the following year. In 1845, a year after the bank received a UK Royal Charter,
it established agencies in Athens and Patras, and appointed special agents in Venice and Trieste.