I don't believe for one moment that the onus of proof is on me, Sminky. You are the one with the contentious and unproven theory that between 650BC (Why on earth that date?) and 1850 people were not paid to perform 'folk' music. An art form for which you refuse to provide a definition anyway.

But, as it happens, one doesn't have to look too far. So how about the following -

BARD. The word is a loanword from descendant languages of Proto-Celtic Bardos, ultimately from Proto-Indo-European: "to raise the voice; praise". The first recorded example is in 1449 from the Scottish Gaelic language into Lowland Scots, denoting an itinerant musician, usually with a contemptuous connotation. The word subsequently entered the English language via Scottish English.

Secondly, in medieval Gaelic and Welsh society, a bard (Scottish and Irish Gaelic) or bardd (Welsh) was a professional poet, employed to compose eulogies for his lord (see planxty). If the employer failed to pay the proper amount, the bard would then compose a satire. (c. f. fili, fáith). In other European societies, the same function was fulfilled by skalds, rhapsodes, minstrels and scops, among others.

Bards or filid were those who sang the songs recalling the tribal warriors' deeds of bravery as well as the genealogies and family histories of the ruling strata among Celtic societies. The pre-Christian Celtic peoples recorded no written histories; however, Celtic peoples did maintain an intricate oral history committed to memory and transmitted by bards and filid. Bards facilitated the memorization of such materials by the use of poetic meter and rhyme.

The Bardic tradition ran from Pre-roman times to the middle ages (In Ireland) There is ample documentary evidence. Sorry if it doesn't fit with your views.

A little further search and a little later on we find Minstrels and troubadours.

A minstrel was a medieval European bard who performed songs whose lyrics told stories about distant places or about (real or imaginary) historical events. Though minstrels created their own tales, often they would memorize and embellish the works of others. Frequently they were retained by royalty and high society. As the courts became more sophisticated, minstrels were eventually replaced at court by the troubadours, and many became wandering minstrels, performing in the streets and became well liked until the middle of the Renaissance, despite a decline beginning in the late 15th century. Minstrelsy fed into later traditions of itinerant entertainers, which continued to be moderately strong into the early 20th century, and which has some continuity down to today's buskers or street musicians.

Want some Renaissance stuff?

By the middle of the 15th century, composers and singers from the Low Countries and adjacent areas began to overspread Europe, moving especially into Italy where they were employed by the papal chapel and the aristocratic patrons of the arts, such as the Medici, the Este family in Ferrara, and the Sforza family in Milan. They carried their style with them: smooth polyphony which could be adapted for sacred or secular use as appropriate. Principal forms of sacred musical composition at the time were the mass, the motet, and the laude; secular forms included the chanson, the frottola, and later the madrigal.

Notice a pattern here? Throughout the entire period you refer too people were paid, retained, whatever you would like to call it, to perform music. The music was telling of current events and was of the current style. In other words, that dreaded term you will not describe, FOLK music. Non of them worked on the fringes. None were trivialised. They were important members of society.

Now, having said all that, they were no more important than those unpaid farm labourers singing in pubs and modern football hooligans chanting on the terraaces when it comes to their contribution to folk music. But to deny their existance at all. A mistake surely?

And I still want to know how 650BC fits in:-)

Cheers

Dave