Given these, it wouldn't be in the least surprising if some Dutch East India company coins turned up somewhere on the northern coats of Australia, either as a result of shipwreck or indirect contact via a trading vessel from what is now Indonesia.
There is news today of some coins doing exactly that. The interesting thing is that they appear to have been found alongside some coins from the Kilwa sultanate in East Africa.
This is in fact not new news, more rediscovered news. The coins have been known for some time and are in the PowerHouse Museum in Sydney.
The PowerHouse Museum acquisition record suggests that the Kilwa and the VoC coins represent two separate deposits, perhaps as a result of two shipwrecks separated by a couple of centuries.
Given however that the actual details of the find and their discovery are vague, there remains the possibility that they are a single deposit
This might seem surprising, but not very. Somalis have been crewing dhows across the Indian ocean for millenia. And Somali sailors are known to have worked on British vessels in the nineteenth century, establishing migrant communities in Cardiff and Liverpool.
There's no reason why some Somali sailors did not sign on to work on a Dutch ship - and we might even be able to find records to that effect. The date of 1690 for the VoC coins gives us the earliest possible date for the coins ending up in Australia, but given that coins are fairly indestructable, they could have ended up in Australia a hundred years later.
The same with the Kilwa coins - they could have been loose change, but given there age that seems unlikley, but they could have been used as counters in a game, or simply kept for sentimental value. The fact that the only other Kilwa coin to have been found outside of East Africa was found in Oman points to them being carried along the spice route.
We can spend all day waving our hands and speculating. We simply don't know. Like Roman style pottery in Bali, they'll probably remain one of these little tantalising enigmas of history.
But, if it is a shipwreck, and other evidence is found to date it more securely, we could probably trawl the VoC records to see if there is evidence of Somalis or other East Africans crewing ships ...