Henry was literally beset on all sides as he survived assassination attempts, put down rebellions in Scotland and Wales (I think I will next look into the heroic Owen Glendower) more than once, rebellions within England with the rallying cry "King Richard is alive!", and later the opposition of his cold hearted son, Henry of Monmouth, who was itching to be Henry V. And there was always the problem of money - the parliament never seemed to make quelling rebellions any easier - causing the royal entourage to be seriously reduced.
Henry IV, as presented by Mortimer, was one of those men for all seasons to me, by power of his very survival through stiff odds, and his pragmatism in doing what needed to be done to hold the kingdom together. Though his time as king was brief, he is an object lesson for capable government in very tough times.