Giovanni Duns Scotus was a medieval Scottish philosopher and theologian, born around 1266. He is best known for his contributions to scholasticism, particularly in the areas of metaphysics and ethics. Duns Scotus emphasized the importance of individual existence and the concept of univocity of being, which means that being is understood in the same way across different entities. His work influenced later thinkers, including Thomas Aquinas and Martin Luther. Duns Scotus is often associated with the idea of the Immaculate Conception of the Virgin Mary, arguing that she was conceived without original sin. His writings continue to be studied for their depth and complexity in philosophical and theological discussions.