1570s, "likeness made to scale; architect's set of designs," from Middle French modelle (16c., Modern French modèle), from Italian modello "a model, mold," from Vulgar Latin *modellus, from Latin modulus "a small measure, standard," diminutive of modus "manner, measure" (from PIE root *med- "take appropriate measures"). Sense of "a thing or person to be imitated" is from 1630s.
If the Model Boy was in either of these Sunday-schools, I did not see him. The Model Boy of my time—we never had but the one—was perfect: perfect in manners, perfect in dress, perfect in conduct, perfect in filial piety, perfect in exterior godliness; but at bottom he was a prig; and as for the contents of his skull, they could have changed place with the contents of a pie and nobody would have been the worse off for it but the pie. ["Mark Twain," "Life on the Mississippi," 1883]
Meaning "motor vehicle of a particular design" is from 1900 (such as Model T, 1908; Ford's other early models included C, F, and B). Sense of "artist's model" is first recorded 1690s; that of "fashion model" is from 1904. German, Swedish modell, Dutch, Danish model are from French or Italian.