25 Drachmai black front

The Ionian Bank was a British chartered institution operating primarily in the Ionian Islands and later mainland Greece — founded in London in 1839, it held a note-issuing privilege that outlasted most private banks of its kind in the region. By the time this series was issued, the bank had been operating for half a century under a charter that was repeatedly contested by Greek authorities who wanted note-issuing rights consolidated under the National Bank of Greece.

Waterlow & Sons handled the printing, as they did for much of the bank's output throughout the nineteenth century. The "black front" designation distinguishes this from color variants in the same denomination series — a printing distinction, not a later classification.