A Research Oral on the Existence and Nature of Chamber Music Before 1750

During my many hours of research for this task, I found some very helpful resources on the subject of chamber music. Most of these books and web sites were arranged very carefully and neatly in, mainly two different ways - in periods, classical, romantic and contemporary and by composer. I found this organization very helpful and convenient but what struck me was that when the resources were listed by period, they had always seemed to skip the baroque period and when they were listed by composer, they always seemed to skip composers before 1750. I wanted to know why there was such a giant gap at the beginning of such a large discipline as "chamber music". I then discovered that chamber music ensembles almost never choose works older than 1750. This raised a completely new set of questions.
Is music earlier then 1750 unworthy of performance? Are the instruments that they were written for obsolete? Did chamber music exist before 1750? When did the music that we now refer to as 'Chamber-Music' begin - when did composers start writing for ensembles in a manner that we now call chamber music? Did the String Quartet simply appear out of no-where or are there ancestors of it?
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