Neoplatonists were philosophers who emerged in the 3rd century CE, building on the ideas of the ancient Greek philosopher Plato. They emphasized the existence of a single, ultimate source of reality called the One, from which all things emanate. Neoplatonism sought to explain the relationship between the material world and the spiritual realm, advocating for the pursuit of higher knowledge and the soul's return to the divine. Key figures in Neoplatonism include Plotinus, who is often considered the founder of the movement, and Porphyry, who expanded on his teachings. Neoplatonism influenced various fields, including Christianity, Islam, and Renaissance thought, promoting ideas about the nature of existence and the importance of inner contemplation.