Henry Percy, 9th Earl of Northumberland (1564 - 1632) is better known for the circles he moved in than for his own achievements.

Although his title was from the north of England, Percy's estates were in the south at Petworth House and at Syon House, a few miles north of Richmond-upon-Thames.

Henry employed Thomas Percy (c 1560 - 1605) as a rent-collector at Syon House. Thomas, the great-grandson of the 4th Earl of Northumberland, was very unscrupulous. He had 34 charges of dishonesty brought against him. Henry was a Catholic sympathiser and suffered under the punitive laws passed by Elizabeth I in the 1580s. When it became clear that the Protestant James VI of Scotland was likely to succeed Elizabeth, Henry sent Thomas on a secret mission to James' court three times in 1602. He said that English Catholics would accept James as king if he reduced the persecution of Catholics. In the event persecution increased. In desperation, Thomas Percy went on to become one of the five conspirators in the Gunpowder Plot of 1605. When the plot was discovered Thomas Percy fled and was besieged at Holbeache House in Warwickshire. On November 8th 1605, a marksman shot dead both Robert Catesby and Thomas Percy with a single bullet. As a result, Henry Percy was suspected of being part of the plot and spent the next 16 years as a prisoner in the Tower of London.

Henry Percy met friends while in the Tower; these included Thomas Harriot and Sir Walter Raleigh. They discussed advanced scientific ideas and smoked tobacco. Harriot had been a navigational tutor to Sir Walter Raleigh and his captains. From 1598 (or possibly from 1607) Harriot lived in Syon House, Henry's estate near Richmond. There he used a telescope to make a map of the moon several months before Galileo did the same. He may have been the first person to observe sunspots.

The School of Night

In Shakespeare's "Love's Labour's Lost" (1594), there is a mention of the "School of Night". It is now usually accepted that this refers of a circle of scientific investigators which met at Syon House. Thomas Harriot and Christopher Marlowe were members. As a result, Henry acquired the nickname "The Wizard Earl". The astrologer John Dee was also a friend of Henry. There is no evidence that William Shakespeare was involved, but it is possible he was.