Within the confines of the UK, I suppose it depends on how you look at it.
You could argue it's a whole new currency at decimalisation, or just a simple refresh in how it works.
You could argue that the British penny only existed since the UK formed in 1707; the fore-runners being English / Scottish options. The Scots Penny didn't turn up until early 12th century. England as a unified nation didn't exist until about 927 after the successful conquest of viking York. So that would the date for first truly English penny, though some of the earlier forerunner kingdoms used the penny too.
And that's before you even consider could you argue about the “true” penny dying out in 1796 when the last (circulation) silver pennies were struck?
But I'm rambling waaaaay off topic. But it's just such an interesting thought. 🤔
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From a purely mathematical point of view, I like the old L/s/d system too. Like 12 is just such a fantastic number for currency having loads of multiples, and many of those multiples can be broken down too. So 240 pennies to the pound is a really amazing number.
But I get that 100 pennies is a lot easier to work with. Much less complex, and it makes it easy for foreign transactions as virtually everyone uses 100. If I recall correctly, its Mauritania & Madagascar which are technically non-decimal but in both cases, their subdivision is so worthless that its not actually used.
(I think the Sovereign Order of Malta retains a base 12 currency, but they're a weird non-nation organisational nation thingy)