Chronicle of Gregory 1403-1419. Jul 1415. And he roode forthe hys way tylle he cam to Hampton, and there he mosteryd hys mayne. And there were certayne personys that had caste to slayne oure kynge, but God that knewe alle trougthe, he sende warnynge to oure kyng; and hys enmys, the whiche namys folowythe aftyr, Syr Richarde Camborowe (age 29)¹³, Erle of Cambryge, Syr Harry, Lorde Scrope (age 42), ande Syr Thomas Gray (age 30), knyght, with moo of hyr assent, [th]e whiche personys were a-restyde and put in the preson, ande do to dethe.

Note 13. Camborowe. Conysborughe in Vit.

On 31 Jul 1415, when King Henry V of England (age 28) was in Portchester Castle, Hampshire [Map] preparing to invade France, Edmund Mortimer 5th Earl March 7th Earl Ulster (age 23) revealed the Southampton Plot to him. Henry Scrope 3rd Baron Scrope Masham (age 42), Thomas Grey of Werke and Heaton (age 30), and Richard of Conisbrough 1st Earl Cambridge (age 30) were intending to replace King Henry V of England (age 28) with Edmund Mortimer 5th Earl March 7th Earl Ulster (age 23) as King of England based on Edmund Mortimer 5th Earl March 7th Earl Ulster (age 23) having a better claim to the throne being descended from Edward III's second son Lionel Plantagenet 1st Duke of Clarence whereas King Henry V of England (age 28) was descended from the third son John of Gaunt 1st Duke Lancaster.

Robert Willoughby 6th Baron Willoughby (age 30), Richard de Vere 11th Earl of Oxford (age 29), Thomas Montagu 1st Count Perche 4th Earl Salisbury (age 27) and Thomas Camoys 1st Baron Camoys (age 64) sat in judgement.