Leonhard Euler

The Swiss mathematician Leonhard Euler lived during the 18th century. Like many other great mathematicians he researched and made important contributions to every mathematical field.

Euler wrote more scientific papers than any mathematician before or after him. In 1911 scholars began to publish his collected works. Wiliam Dunham wrote about this collection in 1994:

"To date there are well over 70 volumes on the shelves (but who's counting?) and new ones will appear sporadically well into the twenty-first century. As a typical volume runs to 500 large pages and weighs about 4 pounds, the overall bulk of his Opera Omnia stands at more than 300 pounds! No other mathematician can match this poundage."

Euler even found a new theorem in Euclidean geometry, a field which had been looked at as completed. Here's a short explanation of this theorem:

The three heights of a triangle meet in point H, and the three perpendicular bisectors in point M. Point E in the middle of the line between H and M is the center of a circle on which are all the intersections of the heights and the perpendicular bisectors with the triangle.

Both of Euler's parents were very religious, his father being a pastor and his mother the daughter of a pastor. For Euler himself, religion was very important too; he even studied theology. For many mathematicians between the 16th and 18th century, their belief was a reason for studying mathematics. For them, math was a tool to decipher God's design of our world. With every new discovery, they felt a step nearer to understanding nature and by this understanding God.

With barely twenty years, Euler moved to Petersburg where he spent most of his life. Together with his wife, he had 13 children of which 5 survived. He enjoyed his kids very much and later also spent a lot of time with his grandchildren.

Euler didn't only make a lot of research, but also wrote a number of school books. Through that he played an important part in defining the mathematical symbols we use today.