Word Origin & History
toO.E. to "in the direction of, for the purpose of, furthermore," from W.Gmc. *to (cf. O.S., O.Fris. to, Du. too, O.H.G. zuo, Ger. zu "to"), from PIE pronomial base *do- "to, toward, upward" (cf. L. donec "as long as," O.C.S. do "as far as, to," Gk. suffix -de "to, toward," O.Ir. do, Lith. da-). In O.E.,
the preposition (go to town) leveled with the adverb (the door slammed to) except where the adverb retained its stress (tired and hungry too); there it came to be written with -oo (see
too). The nearly universal use of to with infinitives (to sleep, to dream, etc.) arose in M.E. out of the O.E. dative use of to, and helped drive out the O.E. inflectional endings (though in this use to itself is a mere sign, without meaning). Commonly used as a prefix in M.E. (to-hear "listen to," etc.), but few of these survive (to-do, together, and time references like today, tonight, tomorrow -- Chaucer also has to-yeere). To and fro "side to side" is attested from 1340. Phrase what's it to you "how does that concern you?" goes back a long way:
"Huæd is ðec ðæs?"
[John xxi.22, in Lindisfarne Gospel, c.950]