The alexandrine is English for lines of verse that are in iambic hexameter—that is, lines of verse having 12 syllables per line—that traditionally are divided into two groups of 6 syllables each with a fixed medial pause, or caesura, and with strong stresses on the sixth and last syllables. A French invention from the twelfth century, the alexandrine was primarily used by the French until the advent of vers libre, or free-verse, in the nineteenth century. It is the standard line of traditional French poetry since the sixteenth century and has an importance comparable to blank verse in English poetry. The name itself may have derived from a poem about Alexander the Great, and it circulates in the bloodstream of anyone classically educated in French poetry.