Was it always scripted?
Some time at the turn of the 20th century, although the fakery didn't truly take hold until the 30's. I've heard it said that the massive loss of life of the first world war drained so much athletic talent and knowledge that subsequently the entertainment side won out over the real deal.
At the very least, wrestling in the 1800s and prior was largely unscripted if not almost completely out-and-out competitive matches. A "worked" match at this time would be more like a fixed fight in boxing than the pantomime we see in the ring today.
You mean professional wrestling. There is a 1936 movie, Nothing Sacred, in which the main characters attend a wrestling match which has a very scripted look about it.
Scripted but interesting
some would argue Gotch/Hackenschmidt in the 1910s was 'worked'... at the very least Gotch is accused of using a ringer to weaken Hackenschmidt in training... and further rumors that Hackenschmidt took a dive in the rematch...
so odds are that it was at least 50/50 work/shoot by that time...
and it was an open secret if not common knowledge among the fandom that it was 100% worked by the 1930s... as jokes were made about it in several Films of the era...
It's always been scripted.
1953
Wrestling has always been scripted.....!!
It's always been worked in some form or another.
Since day one.
Always had predetermine endings