The Erat manufactory, founded by Jacob Erat at 100 Wardour Street, Soho, is first recorded in an advertisement in the Times of 3 January 1798. In 1819, the Erat manufactory moved a short distance to 23 Berners Street.

Erat’s eldest sons, Jacob (1799–1836) and James (1801–1858), succeeded to the business on Jacob’s 25th birthday, 8 December 1825. The company continued producing harps until the death of James Erat in March 1858. Between 1821 and 1824 the Erat Company produced on average 6.7 harps per month; according to their serial numbers, approximately 4,500 were made between 1796 and 1858.

This is harp number 1820 so would be from around 1828.

From: Mike Baldwin, Harp Making in Late-Georgian London (London: Bright Light, 2020).