With the Middle English loss of all distinctive inflectional endings for the noun except genitive and plural -s, prepositions acquired a somewhat greater importance than they had had in Old English. Their number consequently increased during the late Middle and early Modern periods. Changes in the uses of certain prepositions are illustrated by the practice of Shakespeare: “And what delight shall she have to looke on [at] the divell?” (Othello); “He came of [on] an errand to mee” (Merry Wives); “But thou wilt be aveng’d on [for] my misdeeds” (Richard III); “’Twas from [against] the Cannon [canon]” (Coriolanus); “We are such stuffe / As dreames are made on [of]” (Tempest); “Then speake the truth by [of] her” (Two Gentlemen); “... that our armies joyn not in [on] a hot day” (2 Henry IV).
Even in Old English times, on was sometimes reduced in compound words like abūtan (now about), a variant of on būtan ‘on the outside of.’ The reduced form appears in early Modern English aboard, afield, abed, and asleep, and with verbal nouns in -ing (a-hunting, a-bleeding, a-praying). The a of “twice a day” and other such expressions has the same origin. In was sometimes contracted to i’, as in Shakespeare’s “i’ the head,” “i’ God’s name,” and so forth. This particular contrac- tion was much later fondly affected by Robert Browning, who doubtless thought it singularly archaic—for example, “would not sink i’ the scale” and “This rage was right i’ the main” (“Rabbi Ben Ezra”).