Monarchial reigns (i) tended to be more (ii), dynastically speaking, than those royal courts in which palace machinations had not become a quotidian affair. In the latter, a pall of complacency would fall over the kingdom so that if suddenly there were an earl with an axe to grind, so to speak, his path to usurpation would be (iii).
Blank (i)
marked by intrigue
characterized by hubris
weakened by attrition
Blank (ii)
imperiled
volatile
robust
Blank (iii)
largely unobstructed
a treacherous one
hardly assured