Sentence:  In all his miscalculations , Stravinsky made the <WSD>fatal</WSD> historical blunder of presuming that he could transform other composers ' inspirations - representing many peoples , time periods and styles - into his own music by warping the harmony , melody , or form , to verify his own experiments . 
Meaning of the word marked with <WSD> tags:  (of events) having extremely unfortunate or dire consequences; bringing ruin