WI: John of Eltham lives
VVD0D95
John of Eltham was Earl of Cornwall and Edward III's oldest brother, he died in 1336 aged 20. What happens if he does not die and lives on to marry and sire...
alternatehistory.com
John of Eltham was Earl of Cornwall and Edward III's oldest brother, he died in 1336 aged 20. What happens if he does not die and lives on to marry and sire children? What effects does this have on things such as the HYW? As well as the whole shebang with his earldom later being elevated to a dukedom, does that still happen? Furthermore, who might he marry?

He was reportedly a successful, if ruthless, military commander in campaigns against the Scots (including the crushing victory at Halidon Hill). So in that sense he could assist his brother in the HYW as a loyal lieutenant (he didn't show any inclination towards revolts/plotting OTL, and the siblings difficult upbringing may have created some solidarity between them).

I'm not sure how Edward worked things OTL, but John could maybe stay behind to govern England in his brother's absence (did he appoint regents when on campaign?). Given his early experience in the area John could also be told to handle the Scots.

The interesting question is who would he marry? English or internationally?

Are there any English heiresses Edward can snap up for his brother? Or any French/continental brides useful for support in the HYW?