Benjamin Banneker (November 9, 1731 - October 9, 1806) was born in Maryland. He was an African-American astronomer, clockmaker, and publisher and was instrumental in surveying the District of Columbia.
Banneker was the son and grandson of freed slaves from Africa. His maternal grandmother was an indentured servant from England who freed, and then married, her male slave. The original family name was Banna Ka, or Bannakay. His father, Robert Bannakay, was notable for having built a series of dams and watercourses that successfully irrigated the family farm where Banneker lived most of his life. Banneker was taught to read and do simple arithmetic by his grandmother and by a Quaker schoolmaster, who changed his name to Banneker.
At age 21, Banneker's life was changed when he saw a neighbor's patent pocket watch. He borrowed the watch, took it apart to draw all its pieces, then reassembled it and returned it running to its owner. Banneker then carved large-scale wooden replicas of each piece, calculating the gear assemblies himself, and used the parts to make the first striking clock ever built in America. The clock continued to work, striking each hour, for more than 40 years.
This event provided the impetus to turn him from farming to watch and clock making. One customer was Joseph Ellicott, a surveyor who had to have a very accurate timepiece to make correct calculations of the locations of stars used to locate the surveyor's position on earth. Ellicott was impressed with his work, and loaned him books on mathematics and astronomy.
His study of astronomy, beginning at age 58, enabled him to make the calculations to predict solar and lunar eclipses and to compile an ephemeris for his Benjamin Banneker's Almanac, which he published from 1792 through 1797. He became known as the Sable Astronomer.
In 1791, he was hired to assist brothers Andrew and Joseph Ellicott to work with French architect Pierre L'Enfant by surveying the Federal District to lay out the new capital of the United States. When L'Enfant was dismissed after numerous blowups, he took his drawings with him, but Banneker was able to recreate them from memory, thus preserving the famous plan of Washington, D.C..
Also in 1791 Banneker wrote to Secretary of State, and author of the Declaration of Independence Thomas Jefferson, with an eloquent plea for justice for African Americans, based on the experience of the colonies of the oppression of Britain and quoting Jefferson's own words. At that time African Negroes were thought to be an inferior race, not able to undertake the full responsibilities of citizenship. As a subtle hint of the capabilities of his people, Banneker included a copy of his newly published almanac with its astronomical calculations. Jefferson acknowledged Banneker's intellectual achievements, but did not help to abolish slavery. Banneker's almanac helped convince many Americans that African-Americans were not intellectually inferior to whites.
In 1980, the U.S. Postal Service issued a postage stamp in his honor.