Thomas Dixon Galpin (1828-1910) was born in Dorchester, England. He was educated at Queenwood College in Hampshire. In 1851, he married Emma Pare and had 13 children. Emma's father introduced him to George Petter, a printer who was looking for a partner. He entered into the printing business with George William Petter.
George William Petter (1823-1888) was born in Barnstaple, England. His father was a postmaster and gave him an evangelical upbringing. This religious childhood affected his choice of material to print or to publish. He started a printing business, in Fleet Street, with his cousin George Edward Petter and Charles Duff, called "Petter, Duff & Company". When both his partners left, he found a new partner in Thomas Dixon Galpin. In 1852, they moved to Playhouse Yard and founded "Petter & Galpin."
Simon Nowell-Smith, The House of Cassell 1848-1958. (London: Cassell and Company Ltd., 1958).