> How can you determine absolute pitch of musical ensembles from times before precise frequency measurement devices were available?
You cant, thats was the whole point of my post. Today we tune to specific frequencies as a base line. In the past it was arbitrary. How far back in the past determines how arbitrary it is.
Thats the whole point, a song that may have survived a long time may have been intended for a very different pitch than it is in modern times. Unless they had some standard way to get an approximate baseline pitch (such as defining a standard for the size of a tuning fork)