In 400 BC, Hippocrates used four separate categories to analyze an individual's personality, including optimism, irritability, depression and sluggishness, according to the book IQ and Personality Tests. Since then, many other people have sought ways to interpret and measure the human personality.

Residents of Idaho will soon have the chance to explore the ancient origins of personality tests during a lecture by Suzanne Stabile, the Times News reports. During a two-day presentation titled Know Your Number, Stabile will teach her audience about the Enneagram.

According to the news outlet, this test gives a person a number from one to nine. Each number correlates to different characteristics, traits, strengths and weaknesses. However, individuals may find that they receive a different number each time they take the test.

The test was created around 345 to 399 AD, having ties to Ponticus, an Egyptian monastic. Although it was passed down orally for generations, it was not put in print until the 1970's, according to the media provider.

Currently, individuals who are interested in analyzing their personal traits and characteristics have the opportunity to take a modern personality test. Many of these tools have built upon the foundation that was laid by ancient exams.