A mythical king of England, and father of King Lear. He built the city of Bath, and dedicated the medicinal springs to Minerva. Bladud studied magic, and, attempting to fly, fell into the temple of Apollo and was dashed to pieces. (Geoffrey of Monmouth.)
“Inexhaustible as Bladud's well.” —Thackeray.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894