1 Prof. Jones: In some versions of the myth, Arthur's shield Wynebgwrthucher is known as Prydwen.
2 Monty: I thought Prydwen was the name of Arthur's ship.
3 Prof. Jones: Yes, that too, according to some other accounts.
4 Monty: How does anyone confuse a shield and a ship?
4 Prof. Jones: Yet other accounts say they had some very strong beer.

This seems to be an issue with many old myths and legends that get told and retold over the centuries. They all start to become inconsistent, and what was named one thing in one telling is named something else in another telling, while the original name is applied to some other thing completely, and some hero is the child of peasants in one story, but is the offspring of a king and a nymph in another, and is born from a pomegranate in another.

Yeah, whoever decided kids could be born from pomegranates was definitely onto some very strong beer.