Leonhard Euler is best known as a prolific mathematician, but he also made notable contributions in optics and astronomy. He was born in Basel, Switzerland on April 15, 1707, the son of Paul Euler, a Protestant minister, and Margaret Brucker, the daughter of a Protestant minister. Accordingly, Leonhard Euler was raised to follow suit and join the ministry, but his father had sparked his interest in mathematics at a young age, and this interest was further cultivated at the University of Basel, which he entered at the age of fourteen. His prodigious ability in the field impressed renowned mathematics professor Johann Bernoulli, who allowed Euler to visit with him on Sundays to discuss any difficulties the young scholar had in understanding the advanced books on mathematics that he had recommended. Nevertheless, even in 1723, Euler still appeared to be set on a course that would lead him to the church, having gained his Master's degree in philosophy and embarked on studies of theology. Soon after, however, with the help of Bernoulli, Euler convinced his father to permit him to study mathematics instead.