Quote: I don't think cordage making is an invention of our species, but something probably far older, so is it conceivable that the sling itself is an concept-invention-discovery we can't lay claim to?
caught my eye.
I mean the first cordage, would have been vines. Abundant, ready made and often bound round something to indicate an actul use.
As to when someone started to make their own 'vines' - who knows.
Well, nobody knows

But what species do you think invented non-vine cordage ?
The neanderthals ? - who were ahead of our own branch of humanity in pretty much all civilised aspects.
Or some others ?
And you are all ignoring the one soceity that we Know had shrines to slinging.
The pre-spanish chomorro
There are enormous slingstones all over the islands that were possibly used as shrines.
If any culture had a god or gods of slinging, it's micronesia and the chomorros.
The problem there is the spanish had 500 years to quash and destroy the old beliefs and language.
And under that kind of onslaught, where nothing was written down, even spoken records are often lost.
But the odds are very good that there was a god or gods of slinging on guam and the surrounding islands.
From guampedia:
Quote:In addition to witnessing fights among the CHamorus, the Spanish also observed the spiritual aspect of native warfare. The CHamorus believed in the presence of the mananiti, or ancestral spirits, and the power of these spirits to assist them in fishing, farming, and even in battle. They believed the ancestral spirits lived on in the skulls of their deceased ancestors and that the makana—the practitioners of healing and magic—had the power to communicate with them. The makana would take out the skulls, lay them out and invoke upon them their requests for help and good fortune. In some cases, the makana would take the skulls and place them on the actual battleground. Victory, of course, was seen as a favorable response by the mananiti.
The CHamorus continued to rely on the skulls for spiritual strength, even in their battles against the Spanish in the late 17th century. The makana, in response to Spanish efforts to missionize and colonize the islands, motivated the CHamorus to fight against the priests and soldiers. Jesuit Father Diego Luis de San Vitores, who headed the newly established Catholic mission, worked hard to remove the authority of the makahna by criticizing them whenever possible and ordering the destruction of the skulls. In one account of a battle in 1671, the natives dug trenches at the advice of a council of makhana and placed in them the skulls of their ancestors. The CHamoru warriors fought with new spiritual vigor; however, the Spanish, with their advanced weaponry, defeated the natives. The Spanish then “cast the skulls on the ground and trampled on them.”
So maybe not a specific god, but there were definitely spirits that helped in warfare and warfare was heavily sling biased.
The above account is interesting in that it doesn't mention the length of time it took the spanish defeat the chamorru.
And as all accounts were written by spanish missionaries - one jesuit brother in particular, it's not exactly an unbiased account.
I have read the jesuits full accunt of chomorro culture, but that was a few years ago. I should have a pdf somewhere.
I know roman sent me a copy.
But it looks like they probably didn't have gods as such.
But shrines with huge slingstones - there definitely are.
We can speculate that specific ancestral skulls might have been specific to a particular sling-stone shrine.
But we'll probably never know.