Fust came from a family which had been settled at Warnham, near Horsham, since the early 14th century.
Fust had been present at the shire court held at Chichester for the Sussex elections to the Parliaments of 1407, November 1414, 1415, 1419, May 1421, December 1421 (the occasion of his own single return for Chichester), 1422, 1425 and 1426; and he again attested the shire indenture in 1433. Furthermore, his name had been put down by the sheriff of Surrey and Sussex as a pledge for the appearance in the Parliament of May 1421 of all the burgesses elected from Surrey. Fust’s continuing connexion with the citizens of Chichester is indicated by his appearance as a witness to deeds on behalf of Geoffrey Hebbe (in March 1422) and William Hore (in May 1434).
