Birmingham's principal tradesmen during the English Civil War were the smiths, who were called upon to manufacture over 15,000 sword blades, these are supplied to Parliamentarian forces only. One of the town's leading minds, 'Nathaniel Nye' is recorded as testing a Birmingham cannon in 1643. Nye also experimented with a saker in Deritend in 1645. From 1645 he became the master gunner to the Parliamentarian garrison at Evesham and in 1646 he successfully directs the artillery at the Siege of Worcester, detailing his experiences and in his 1647 book "The Art of Gunnery", believing that war is as much a science as an art.