Warfare introduced a great many Cornishmen into the glamorous circle of the fighting nobility, and it was only natural that in peacetime demobilised Cornish soldiers should further their interests by profiting from these connections. Although he held no lands in the county, Aymer de Valence, the earl of Pembroke, twice influenced the personnel of the earldom, securing the sheriff-stewardship for two of his retainers, Sir Roger Ingepenne of Berkshire and Sir Thomas l’Ercedekne. Both Ingepenne and l’Ercedekne had fought alongside the earl, which helped recommend them to him for peacetime employment. Across the century, the Courtenay earls of Devon raised as many as fifty-nine fighting men from Cornwall. It is therefore no surprise that a few Cornish gentlemen, Richard Kendale and John Tregorrek among them, appeared as retainers on Edward Courtenay's livery roll of 1384–5. As the family held some lands to west of the Tamar, they employed a certain John Isaak as receiver in Cornwall and Devon, Isaak having sat in parliament for Truro and Helston in 1364–5. Just after the Great Revolt, the Crown came to recognise the family's influence by appointing Earl Edward to the Cornish bench. Since the earls of Warwick owned three manors in Cornwall, they too employed local men to look after their interests. In the 1390s, for example, the lawyer Roger Trewythenick is found serving as their steward locally, and on one occasion the family ‘made representations’ to the Black Prince about their villeins. Magnate connections of this kind helped to widen the county's horizons. Richard Germyn even wrote to his employer, one William Stoner: ‘as to your tenaunts in Cornwale, thei be as trew unto you as y can understond as any tenauntes that ye have’.

Many lords from east of the Tamar held estates in the peninsula, fostering ties with key local landowners and officials to ensure their better protection. It is illustrative of this that in 1400 the bailiff of the Devonian Sir John Dinham paid the sheriff of Cornwall 6s. 8d. for a writ served against the tenants of Blisland.