Heroic verse consists of the rhymed iambic line or heroic couplet. The term is used in English exclusively.
In ancient literature, heroic verse was synonymous with the dactylic hexameter. It was in this measure that those typically heroic poems, the Iliad and Odyssey and the Aeneid were written. In English, however, it was not enough to designate a single line of iambic pentameter (an iambic line of five beats) as heroic verse, because it was necessary to distinguish blank verse from the distich, which was formed by the heroic couplet.
In French the alexandrine has always been regarded as the heroic measure of that language. The dactylic movement of the heroic line in ancient Greek, the famous ρυθμός ἥρώος, or "heroic rhythm", of Homer, is expressed in modern Europe by the iambic movement. The consequence is that much of the rush and energy of the antique verse, which at vigorous moments was like the charge of a battalion, is lost. It is owing to this, in part, that the heroic couplet is so often required to give, in translation, the full value of a single Homeric hexameter.
It is important to insist that it is the couplet, not the single line, which constitutes heroic verse. It is interesting to note that the Latin poet Ennius, as reported by Cicero, called the heroic metre of one line versum longum, to distinguish it from the brevity of lyrical measures.
The current form of English heroic verse appears to be the invention of Chaucer, who used it in his Legend of Good Women and afterwards, with still greater freedom, in the Canterbury Tales. Here is an example of it in its earliest development: