Career
He was initially appointed to the court by Maryland Governor John Lee Carroll in 1878 and elected to the position in November 1879. He held on to the position until 1883. He also worked as the Director of the Chesapeake and Ohio Canal, as well as a state director for the Baltimore and Ohio Railroad.
He also was an editor for several newspapers, such as the Frederick Examiner, the Federal Gazette and the Baltimore Chronicle, for which he was also the proprietor.
Neilson was also a cousin of the poet, Edgar Allan Poe. However while still family, Edgar and Neilson were rivals.
At one time, Edgar referred to Neilson as "the bitterest enemy he had in the world". The reasoning behind this charge is unknown.
On October 3, 1849, Edgar Allan Poe in backroom of Ryan"s inn and tavern, delirious.
Soon afterwards Edgar died. Edgar"s hearse and a headstone of white Italian marble, were paid for by Neilson. He was the father of John P., the Attorney General of Maryland from 1891 until 1895.