Portrait of Stephen Bull, Master Gunner of England, half-length, in a black doublet and a gorget, his left hand resting on the hilt of his sword

The portrait bears the coat-of-arms and crest which were granted, on 20 August 1601, to Stephen Bull, Master Gunner of England. The form of the mantling and the helmet on the coat-of-arms are identical to a fascsimile of the armorial bearings in the archives of the College of Arms. This was made on 18th May 1640 when the patent was in the possession of William Painter of Gillingham, Kent, one of the King's Gentleman Pensioners. This suggests that the Herald Painter responsible for the Letters Patent may have added the Armorial Bearings to the portrait, or alternatively that an exact copy was made from the patent.

Stephen Bull trained in martial affairs from an early age and served the Crown in the reigns of King Henry VIII, King Edward VI, Queen Mary and Queen Elizabeth I. He was appointed a Master Gunner of England by Queen Elizabeth I. It seems likely that the sitter was the same Stephen Bull who was buried at St. Katherine by the Tower, in the City of London, on 31 May 1607.

The increasing use of artillery in 16th and 17th Century warfare made the office of Master Gunner one of growing importance in most European Kingdoms. A Master Gunner's chief responsibility seems to have been the development, manufacture and supervision of both artillery and gunpowder.