A few points relating to the above:

- when the proto-Gypsies fled northern India they took their caste system with them. Musicians were one of those castes but there were many others - you wouldn't get a violinist to fix buckets.

- the musician class did *not* play Gypsy folk music. That was the music of the Gypsies in general and it was not an instrumental tradition at all - in Hungary the nearest they got to an instrument was whacking a metal jug like an udu.

- what the musician class *did* do was to play the music of their host cultures, well enough for them to ne sought out as experts at it. This might be Jewish wedding music in Ukraine, Romanian and Hungarian fiddle music in Greater Hungary, and from what Sian says, harp music in Wales. They didn't fuse these host musics with Gyosy folk tradition - there is nothing like those melismatic vocals and highly ornamented violin melodies in Gypsy folk (which goes in for rather simple tunes extended with rhythmic drones and call/response structures).

So the role of Gypsy musicians was pretty much that of professionals of any ethnicity anywhere - to preserve and develop the idioms their hosts already had, and do it better. Not to import material from other places and earlier centuries.