Protestant thought refers to the beliefs and ideas that emerged from the Protestant Reformation in the 16th century, primarily led by figures like Martin Luther and John Calvin. It emphasizes the authority of the Bible over church traditions, the importance of personal faith, and the concept of salvation by grace through faith alone. Central to Protestant thought is the idea of the "priesthood of all believers," which suggests that individuals can have a direct relationship with God without the need for intermediaries like priests. This has led to diverse interpretations and practices within various Protestant denominations, fostering a rich tapestry of beliefs and worship styles.