Two King's Bench lawsuits in The National Archives of the UK contain new information about the activities of castrati working in mid-eighteenth-century London. Monticelli v. Sackville (1748) confirms Horace Walpole's testimony that singers employed by the Earl of Middlesex's opera company received enormous salaries. Manfredini v. Geminiani (1751) preserves details of a contract of employment between singer and impresario that went disastrously wrong for both parties. An account of the London careers of the main protagonists is supplied to contextualise the new information.