These coins can cause some confusion, to people trying to find them in the coin catalogues.
Sumatra is a large island in what is now Indonesia, forming the western shore of the Strait of Malacca with Malaysia on the eastern shore. During the European colonial period, these territories were originally controlled by Portugal; the Dutch took them over in 1641.
During the Napoleonic wars in the early 1800s, the Netherlands found itself annexed and assimilated by the French, becoming a French ally by force; the French thus took nominal control of the Dutch colonies. To prevent this becoming actual control, the British invaded and annexed as many Dutch colonies and territories as they could. They annexed the port of Malacca, as well as strategic ports on the island of Sumatra. This coin was issued for use on British-occupied Sumatra. The coat of arms on the coin is the arms of the British East India Company. After the war, the British gave Sumatra along with many of the other annexed territories back to the newly independent Netherlands.
To complicate things further, merchants in Singapore in the 1830s made evasive imitations of these coins, with similar legends (such as "Island of Sultana").
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis