Manx Shilling
Modern equivalent
14 Manx pence = 1 shilling; £100 sterling = £116 13s 4d Manx
From 1696 the Isle of Man valued its coinage at fourteen pence to the shilling, two more than sterling.
The arithmetic is worth doing, because it shows how far apart two currencies can drift while sharing the same names. A hundred pounds sterling is 24,000 pence. Converted at fourteen Manx pence to the shilling, it becomes 28,000 Manx pence, which is 116 pounds with 160 pence left over — and 160 pence is thirteen shillings and fourpence. Every Manx coin was the same denomination as its English counterpart and worth less.
The island did not give this up willingly. The House of Keys rejected adopting sterling in 1834. The British government overruled them and imposed it in 1839, declaring that the currency of Great Britain should become the currency of the Isle of Man, and the Copper Currency Act of 1840 reset the shilling to twelve pence. Older Manx coins were recalled, though Manx coinage remained legal until decimalisation in 1971.
The modern Manx pound sits at parity with sterling and is backed by Bank of England notes, but the relationship is still not symmetrical: Manx notes are not legal tender in the United Kingdom, while Bank of England notes are legal tender on the island.