Sentence:  "Northumberland," thou Ladder wherewithall / The mounting "Bullingbrooke" aſcends my Throne, / The time ſhall not be many houres of age, / More then it is, ere foule ſinne, gathering <WSD>head,</WSD> / Shall breake into corruption ... 
Meaning of the word marked with <WSD> tags:  Denouement; crisis.