Robin: So why is that so important then Mr. Foreman ?

Foreman: Well its like the old Parliament of the 3 Estates in France. We get plenty of written records about the nobility and plenty of records about the clergy, but we rarely get written records from the commoners except occasionally in wills or court cases. You see you don't get any written records about the Morris after 1367 until it features in courtly circles many years later when John of Gaunt's descendant Henry VII comes to the throne.

Robin: What about this reference on the Plymouth website about the Morris in Lanherne in Cornwall ?

Foreman: Let's have a look at that.

Itm. Iiij dosyn bellis for the Moruske of Betty iij s.

It. Ij quayers p[aper for the moruske of Betty vij d.

Ah Robin my little chucker lucker. I've got hopes that you might make a Morris Dancer when you grow out of that infernal coltishness, but I'm afeared we'll never make a scholar out of you. What that refers to in the word "moruskes" is not the Morris but the making of a mask or masque (disguise) for a Christmas pageant or play. Betty is a place name. Dull boy.

No, if you're looking for written records you'll find some concerning the marriages of Henry VII's kids to Spaniards. Now Henry's claim to the throne was somewhat tenuous to say the least

Quote Marriot Edgar here:

"Henry the Seventh of Engaland
Wasn't out of the Royal top drawer,
The only connection of which he could boast,
He were the king's nephew's brother in law."

Howsomedoever, we can see that he was a genuine if illegitimate descendant of John O'Gaunt by the way he immediately married his kids off to the royal line of Castile AND celebrated the nuptials with a bit of Morris. After that date you get more written references to the Morris either because a) the church sanctioned the Whitsun Ales in order to raise money or b) Puritans couldn't abide it or c) dramatists of the age of Shakespeare threw in a Morris dance when their plays were getting too tedious to bear any longer.