And it's been a tradition for nearly a thousand years, beginning as early as 1176 when the first judged competition took place. In those days, bards were singers who exalted the bravery and good deeds of the warriors and nobles who paid for their services. They were also the keepers of the oral history, which is probably why Edward I, the English king who nearly choked the life out of the Welsh in the 13th century, didn't like them very much. He must have sensed they wouldn't say nice things about him.
Edward I is said to have ordered five hundred bards burned at the stake as part of his effort to dominate the people of Wales during his Iron Ring days. And it worked. The bardic tradition essentially ended (hard to keep it going when they're all dead). The deed was commemorated seven hundred years later by Hungarian poet, Janos Arany, in his rebel poem, The Bards of Wales. Check it out if you have time.
Bards play a small but important role in my current WIP (see blog title). That is because they are symbolic of a sort of passive resistance. Though Edward did put a stop to the bardic tradition at the time he did not suffocate it completely. The Welsh have stubbornly held on to their language and culture over the centuries, something I felt no shame in exploiting when shaping the world of my post-apocalyptic novels. Er, minus the green robes.
In 1792 the Eisteddfod festival was revived for the first time since Edward's days, and it's been going strong ever since. Held during August, it is host to over 150,000 visitors every year. I'd love to go back to Wales during August sometime and catch a glimpse of the gathering of the bards. What a sight!
**Late edit to post. I found this Antiques Roadshow UK video related to the Eisteddfod and thought I should add it. Neat stuff!