Inspired by this question, this question and this answer, what I am looking for is an early source that makes reference to people no longer prostrating themselves after tefillah. If the source gives a reason as to why "we" no longer do this, so much the better, but for the moment I would be happy with a text that simply records this being the case.
By an "early source", I am ideally looking for something prior to the 18th century, but certainly prior to the late-19th. Alternatively, if there is a text that demonstrates that the custom of not prostrating oneself originates after the 17th century, that would be excellent too.