I was reading Montaigne's essay On Presumption, and was struck by his rejection of the distinction between mind (or, more properly, soul) and body, which is something of a favorite of certain philosophers, poor fellows. I was impressed by the fact that he argued that such a distinction cannot even be properly sustained without the use of "hypocritcal monkey tricks" (why monkey?).
For some reason, I thought that someone of his time would be inclined to make the distinction. I thought the rejection of such dualisms was more of a modern point of view. Dewey, for example, famously rejected the many dualisms which litter the philosophical landscape. I've personally felt that those who profess dualism are being in some respects disingenuous as their conduct in life belies the dualisms they cling to, so I had a certain sympathy with Montaigne's view that they rely on hypocritical tricks, though as noted above I'm not sure they are monkey tricks, whatever that's intended to mean.
Montaigne also writes that the rejection of the soul-body distinction is very Christian, which I confess also took me by surprise. This is due to what used to be called the "resurrection of the body" (who can guess what it is called now?) which it is believed will happen in due time, at least according to the Catholic Credo. Soul and perfect body reunite for eternity.
I thought the rejection of dualism was a modern tendency, prompted in part by the development of the sciences. It's a bit humbling to encounter it in Montaigne, backed up by Catholic doctrine. Nothing new under the sun, indeed.