It's Nos GALAN and Noson GalAN GAEAF, just to get the spellings correct. (Although orthography prior to the 19th C. is, umm, fluid, shall we say.) Calan is from the same root as Calendar, and every month has a 'calan' (the first day of each month. So May Day is Calan Mai. The tune IS Nos Galan, honest it is.

And there are a fair few number of Welsh tunes - certainly more than 6, although that 6 (and other single digit numbers) is tossed around a lot. Obviously this is modified by some other thread which questions how specific you can be with any British Isles tune; the original of Irish Washerwoman was written by a Welshman for Eliz.I , for instance, but no one considers it Welsh ... It also seems to be everyone's default position that, if a tune has a Welsh name and an English name, it must be the *Welsh* that 'borrowed' it. Having said that, there are a lot of imported tunes in Wales - including a large number of our Plygain carols - but then a lot of traditional tunes were written to suit specific Welsh poetic metres so *aren't* adopted from elsewhere.

Dicho is right about the 1000 yrs probably being nonsense - as far as tunes are concerned, anyway. There are some manuscripts around from the 16th century but most collections are from the 18th C. I don't think any books which 'married' tunes with words came out until the 19th C.

sian