Shaplegh was born, probably in the first half of the reign of Richard II, as the youngest of four surviving sons of one of the most prominent men of Exeter. Their father, a prosperous cloth merchant, had regularly held both town and Crown office between 1386 and 1408 and his sons and their offspring were to follow in his footsteps.
For much of the 1420s the parliamentary representation of Exeter was heavily dominated by the Shapleghs, and there can be little doubt that it was the influence of his more prominent relatives to whom Roger owed his return to Parliament in 1427 alongside his nephew John, for whom he had stood surety earlier that year.
