Transportation of goods on rivers have been important throughout history, all the way back to the earliest civilization in Mesopotamia, the Indus valley, Egypt, China and more (this might not be the best source in the world, but this should hardly be a controversial claim).
But these same civilizations were also building bridges across their rivers (If a source is necessary this will have to do).
For this reason, I always assumed that some kind of moveable bridges across rivers (to allow passage without impeding ship traffic) must have been very common, even in ancient civilizations such as -- to name only a few -- Egypt, Mesopotamia, Achaemenid Persia and at the very least Rome and Han or Tang-china -- and perhaps even medieval Europe; I acknowledge that such mechanisms would need maintenance and crew to operate them, and a great deal of technical skill to build, but in this regard the ancient civilizations such as Rome or Han China don't seem to have been lacking.
To my own great surprise, I have not been able to online find any examples of moveable bridges (meant to allow ships to pass under, thus excluding medieval drawbridges, whose use was purely defensive) older than the Old London bridge and this source does not specify directly that this was the first moveable bridge ever
My question is, therefore, when and where is the first time moveable bridges appear in history.
Edit: after a little more searching I did come across the 1174 Gaungji Bridge, which one source I found (whose reliability I strongly doubt, as it is a tourist website, for which reason I do not consider my question answered satisfyingly) claim to be the first movable bridge in the world.