1857 AD., Ionian Islands, British administration, London mint, 30 Lepta, KM 35.

Greece, United States of the Ionian Islands, British occupation, London mint, 1857 AD.,
30 Lepta (ø 16 mm / 1,33 g), 0.925 silver, 1,41 g theor. mint weight, mintage ? , axis coin alignment ↑↓ (180°), plain edge, holed,
Obv.: BRITANNIA. , Britannia seated r. holding shield and trident.
Rev.: ΙΟΝΙΚΟΝ ΚΡΑΤΟΣ. / 30 / 1857 , value number within wreath, state name “Ionian State“ above, date below.
KM 35 .

Year / Mint Mark / Mintage / Details
1834 without point after date
1834 .
1848 .
1849 without point after date
1849 .
1851
1852
1857 without point after date
1857 .
1862

Before the French Revolutionary Wars, the Ionian Islands had been part of the Republic of Venice. When the 1797 Treaty of Campo Formio dissolved the Republic of Venice, they were annexed to the French Republic. Between 1798 and 1799, the French were driven out by a joint Russo-Ottoman force. The occupying forces founded the Septinsular Republic, which enjoyed relative independence under nominal Ottoman suzerainty and Russian control from 1800 until 1807.
The Ionian Islands were then occupied by the French after the treaty of Tilsit. In 1809, the United Kingdom defeated the French fleet off Zakynthos island on 2 October, and captured Kefalonia, Kythira, and Zakynthos. The British took Lefkada in 1810. The island of Corfu remained occupied by the French until 1814.
The Congress of Vienna agreed to place the Ionian Islands under the exclusive "amical protection" of the United Kingdom. Despite British military administration, the Austrian Empire was guaranteed commercial status equal to the UK. The arrangement was formalised with the ratification of the "Maitland constitution" on 26 August 1817, which created a federation of the seven islands, with Lieutenant-General Sir Thomas Maitland its first "Lord High Commissioner of the Ionian Islands".

The United States of the Ionian Islands (Greek: Ἡνωμένον Κράτος τῶν Ἰονίων Νήσων, translit. Inoménon Krátos ton Ioníon Níson, literally "United State of the Ionian Islands"; Italian: Stati Uniti delle Isole Ionie) was a state and amical protectorate of the United Kingdom between 1815 and 1864. It was the successor state of the Septinsular Republic. It covered the territory of the Ionian Islands, in modern Greece, and it was ceded to Greece as a gift of the United Kingdom to the newly enthroned King George I of Greece after the Resolution for union with Greece which was proposed by the Party of the Radicals.

More on https://en.wikipedia.org/wiki/United_States_of_the_Ionian_Islands