In 1841Henry Stothert joined forces with Edward Slaughter to form Stothert & Slaughter which, in 1844, became Avonside Ironworks. Between 1852 and 1856 Henry Grunning joined the company and Henry Stothert left, after which the operation became known as Slaughter, Grunning & Co. Later, in 1864, with Edward Slaughter still in control, the company took advantage of the Companies Acts and became the Avonside Engine Company Ltd. In 1934 the firm went into liquidation and was acquired by Hunslet Engine Company.