"But hollow men, like horses hot at hand,  Make gallant show and promise of their mettle;  
"But hollow men, like horses hot at hand,  Make gallant show and promise of their mettle;  But when they should endure the bloody spur,  They fail their crests, and like deceitful jades,  Sink in the trial."  These lines, which influenced Eliot's title and themes, are from what play featuring a conspiracy of men who, like those of the Gunpowder Plot, resort to violence and who are blinded by their cause?
"But hollow men, like horses hot at hand,  Make gallant show and promise of their mettle;  
{Julius Caesar} by William Shakespeare