E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
To make trim. The Italians say, temperare la lira, to tune the lyre; temperare una penna, to mend a pen; temperáre loriuôlo. to wind up the clock. In Latin, temperare calamum is to mend a pen. Metal well tempered is metal made trim or meet for its use, and if not so it is called ill-tempered. When Otway says, Woman, nature made thee to temper man, he means to make him trim, to soften his nature, to mend him.