David Keirsey expanded on the ancient study of temperament by Hippocrates and Plato.

Entity and relation annotations:
id: 0
type: entity
value: text: David Keirsey
labels: <Person>
id: 1
type: entity
value: text: Hippocrates
labels: <Person>
id: 2
type: entity
value: text: Plato
labels: <Person>