Nagasena was a prominent Buddhist monk and philosopher, known for his role in the Milinda Pañha, a significant text in the Theravada tradition. He engaged in a famous dialogue with King Milinda (Menander I), addressing complex questions about the nature of self and reality, which helped clarify Buddhist teachings. His teachings emphasized the concept of anatta, or non-self, illustrating that what we consider the "self" is merely a collection of changing elements. Nagasena's insights contributed to the understanding of Buddhist philosophy and continue to be studied for their depth and clarity in explaining core principles of Buddhism.