A while back on an occult books group, someone was looking for books in Latin about Astral Projection. Immediately I knew I'd not seen that term in any book old enough to be from the era of Latin writing. This led me to investigate when exactly was the first use of the term "astral projection" and its appearance in English.
Using Google Books, I saw little use of the phrase before the 1890s; though Atkinson's account of "Dream Psychomancy" bears some semblance to the phenomenon :
One morning in December, 1836, he had the following dream, or, he would prefer to call it, revelation. He found himself suddenly at the gate of Major N. M.'s avenue, many miles from his home. Close to him was a group of persons, one of whom was a woman with a basket on her arm, the rest men, four of whom were tenants of his own, while the others were unknown to him. Some of the strangers seemed to be murderously assaulting H. W., one of his tenants, and he interfered. "I struck violently at the man on my left, and then with greater violence at the man's face on my right. Finding, to my surprise, that I had not knocked down either, I struck again and again with all the violence of a man frenzied at the sight of my poor friend's murder. To my great amazement I saw my arms, although visible to my eye, were without substance, and the bodies of the men I struck at and my own came close together after each blow through the shadowy arms I struck with. My blows were delivered with more extreme violence than I ever think I exerted, but I became painfully convinced of my incompetency. I have no consciousness of what happened after this feeling of unsubstantiality came upon me." Next morning he experienced the stiffness and soreness of violent bodily exercise, and was informed by his wife that in the course of the night he had much alarmed her by striking out again and again with his arms in a terrific manner, 'as if fighting for his life.' He, in turn, informed her of his dream, and begged her to remember the names of those actors in it who were known to him. On the morning of the following day (Wednesday) he received a letter from his agent, who resided in the town close to the scene of the dream, informing him that his tenant had been found on Tuesday morning at Major N. M.'s gate, speechless and apparently dying from a fracture of the skull, and that there was no trace of the murderers. That night he started for the town, and arrived there on Thursday morning. On his way to a meeting of magistrates he met the senior magistrate of that part of the country, and requested him to give orders for the arrest of the three men whom, besides H. W., he had recognised in his dream, and to have them examined separately. This was at once done. The three men gave identical accounts of the occurrence, and all named the woman who was with them. She was then arrested, and gave precisely similar testimony. They said that between eleven and twelve on the Monday night they had been walking homewards along the road, when they were overtaken by three strangers, two of whom savagely assaulted H. W., while the other prevented his friends from interfering. H. W. did not die, but was never the same man afterwards; he subsequently emigrated. (Vol. I. p. 142.)
In the past it's probable that these kinds of events would have been attributed to visions through dreams rather than through astral projection. The old time hoodoo concept of "witches" who "ride" you when you sleep also seems to be considered as a practice achieved through something like astral projection.
In fact, the oldest reference to astral projection I can find by that name is 1887, in a fictional book titled Mohammed Benani, where the concept is considered as "theosophy" -- an old word, but in this era usually associated with the Theosophical Society.