He knew the cause of everich maladye,
Were it of hoot, or coold, or moyste, or drye,
And where they engendred, and of what humour.
He was a verray, parfit praktisour.
– Geoffrey Chaucer
The Canterbury Tales, General Prologue. The Physician is an intelligent man of medicine, who knows the cause of every malady – which greatly aids their treatment. He is described as a truly, perfection practitioner.