# On This Day

• ### 9-1-1648

Marin Mersenne died in Paris, France. A mathematician himself, he was even better known for his regular correspondence with the leading French mathematicians of his day.

Marin Mersenne
• ### 9-1-1967

Harvey Friedman was appointed Assistant Professor of Mathematics at Stanford University just three weeks before his nineteenth birthday (he was born Sept. 23, 1948). He is now (as of 2010) a distinguished logician at The Ohio State University.