steel (v.) 1
turn to steel, harden
2H4 I.i.116 [Morton to Northumberland, of Hotspur] from his metal was his party steeled
H5 IV.i.282 [King Henry alone, praying] O God of battles, steel my soldiers' hearts
R2 V.ii.34 [York to Duchess of York] had not God for some strong purpose steeled / The hearts of men, they must perforce have melted
Ven 375 [Venus to Adonis, of her heart] give it me, lest thy hard heart do steel it