Baron Berkeley, also known as George Berkeley, was an Irish philosopher and bishop born in 1685. He is best known for his theory of immaterialism, which argues that objects only exist as perceptions in the mind and do not have an independent existence. His famous phrase, "esse est percipi," translates to "to be is to be perceived," highlighting his belief that reality is dependent on our perception. In addition to his philosophical contributions, Berkeley was also involved in education and the church. He served as the Bishop of Cloyne in Ireland and founded a college in Bermuda to promote education. His work influenced later philosophers, including David Hume and Immanuel Kant.