It's important to remember that Llywelyn ap Gruffydd was the most powerful ruler any of the Welsh Kingdoms had seen since the similarly-named Gruffydd ap Llywelyn, and would therefore have had more men at his disposal than the smaller lords of Wales. Nevertheless, I'd say it was Wales' decentralised nature which allowed for large retinues. The Teulu were made up entirely of Bonheddwyr and Uchelwyr - the freemen and nobles, all landowners, who constituted the bulk of the Welsh population at the time. I think it's fair to say that their loyalty to their lord could only be increased by the aforesaid decentralised nature of the Welsh kingdoms - the Kings/Princes moved constantly around their land, visiting courts at all the different Cantrefi, and so they were able to familiarise themselves with every part of their realm, and, crucially, the powerful individuals therein.
Just my two cents. That's the impression I got from reading on the subject, in any case.
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Last edited by Gorrrrrn; May 25, 2010 at 04:59 AM. Reason: dullness