On this day in 1731, the American astronomer and surveyor Benjamin Banneker was born. He was self-taught and known mostly for his popular almanacs and ephemeris work. The son of a free born black woman and an ex-slave father, he was something of a cause célèbre among the abolitionist movement — both in the United States and overseas. In fact, William Wilberforce discussed Banneker in the House of Commons in his fight to end the slave trade.

Banneker was an outspoken abolitionist. In fact, he used his almanacs to push his ideas on that subject as well as other liberal issues. Included in his 1793 almanac was a correspondence that he had with Thomas Jefferson. It is quite interesting. When he first wrote to Jefferson, Banneker didn’t pull any punches. He confronted Jefferson about his public statements against slavery and his continued private participation and profit in it. Jefferson responded politely.

But what’s most interesting is that in later years, after Benneker was long dead, Jefferson showed how small minded he could be. Clearly, Benneker’s criticisms had stung. In a letter to Joel Barlow, he claimed the letter from Benneker “shows him to have had a mind of very common stature indeed.” Yes, very common of him to mentioned Jefferson’s hypocrisy. Jefferson, being the racist he always was, claimed that Benneker must have been helped in his work by a local Quaker benefactor. There certainly was a mind of very common stature among the two and it certainly wasn’t Benneker.

Happy birthday Benjamin Banneker!