This is an interactive personality test of the "Four Temperaments", an idea from Ancient Greek medicine.

The idea of the four temperaments traces back to an Ancient Greek medical theory that there were four fundamental bodily humors (blood, yellow bile, black bile, and phlegm) which could cause illness if they were out of balance. The terms sanguine, choleric, melancholic and phlegmatic were coined by the Greek physician Aelius Galenus to describe the effect of these humors on human behavior. This idea is perhaps one of the oldest that looks like a theory of personality. The four temperaments have never been a part of modern medicine or psychological science, but remain fairly well known due to their use by self-help and spirituality authors.

The OSPP Four Temperaments Scale (O4TS) is a free and open-source measure designed to match the taker to one of the four temperaments. It was developed by finding questions that statistically predicted self identified temperament in samples of people who already has on opinion on which one they were. See the documentation on how it was developed and is scored here.