Although the duel of 1610 was a confrontation between two individuals, John Egerton and Edward Morgan (II), behind them lay groups of family members and kin which helped occasion and perpetuate the breach. The nature of this wider inter-familial conflict was complex and its causes cannot be reduced to a single event. That said, an inheritance dispute beginning in Flintshire in 1606, which Edward Morgan (I) described as a ‘great styrre & adoe’, can be located as the key moment from which the pulses of antagonism and faction informing the Morgan–Egerton clash radiate. To understand the inheritance case and the origins of the Morgan–Egerton feud, we need briefly to introduce another gentry family: the Mostyns. The Mostyn clan was a link common to both the Egertons and the Morgans, but disputes within this large and powerful family served as a corrosive solvent, dissolving bonds of affinity among the local landed orders and producing instead a volatile compound of enmity in Jacobean Flintshire and Cheshire.

Unlike the Morgans of Goldgreave, the Mostyns could unquestionably be numbered among the preeminent families in north-east Wales. Like many Welsh dynasties they could trace their origins back to native princes, but it was their acquisition of estates across north Wales during the sixteenth century that cemented their place close to the top of the local elite. They took their name from the family's principal residence on the Dee Estuary in Flintshire, only a couple of miles east of Goldgreave. In addition to this seat, however, the family established several cadet houses in Flintshire, Caernarvonshire and Anglesey. The branch which holds our attention was that of Talacre, a residence neighbouring Goldgreave in the parish of Llanasa. The founder of this family line was Piers Mostyn, also known as Peter ap Richard ap Hywel, the third son of Richard ap Hywel of Mostyn. He had numerous chil-dren including his heir, also called Piers, as well as a daughter Jane, who became Sir John Egerton's mother. While Sir John was a minor, living with Sir Rowland Stanley of Hooton, this Piers Mostyn, Egerton's grandfather, was one of the local gentry appointed as guardians to look after his interests.