Kolumban

Σχολαστικὸς κολυμβῶν παρὰ μικρὸν ἐπνίγη· ὤμοσε δὲ εἰς ὕδωρ μὴ εἰσελθεῖν, ἐὰν μὴ μάθῃ πρῶτον καλῶς κολυμβᾶν.
(Philogelos 2a)

A student dunce went swimming and almost drowned. So now he swears he’ll never get into water until he’s really learned to swim. (tr. William Berg)