At the end of the 13th century, in De mensuris, Theodoric of Freiberg, further developed the philosophy of time. Theodoric distinguishes five measures of duration: [4]
- Superaetenitas - the measure of divine being; beyond eternity
- Aeternitas - the measure of the being of divine intelligences "if such beings exist"
- Aevum - the measure of angelic beings, which have a beginning, an everlasting existence, with no change in their substance but change in their accidents
- Aeviternitas - the measure of celestial bodies, which have a beginning and are everlasting but inferior in perfection to angels
- Time - the measure of beings with limited period of existence