Iambic tetrameter is a poetic meter in ancient Greek and Latin poetry; as the name of a rhythm, iambic tetrameter consists of four metra, each metron being of the form | x – u – |, consisting of a spondee and an iamb, or two iambs. There usually is a break in the centre of the line, thus the whole line is: | x – u – | x – u – || x – u – || x – u – | ("x" is a syllable that can be long or short, "–" is a long syllable, and "u" is a short one.) In modern English poetry, it refers to a line consisting of four iambic feet. The word "tetrameter" simply means that there are four feet in the line; iambic tetrameter is a line comprising four iambs, defined by accent. The scheme is thus: x / x / x / x / Some poetic forms rely upon the iambic tetrameter, for example triolet, Onegin stanza, In Memoriam stanza, long measure (or long meter) ballad stanza. Quantitative verse In Medieval Latin The term iambic tetrameter originally applied to the quantitative meter of Classical Greek poetry, in which an iamb consisted of a short syllable followed by a long syllable. Two iambs, or a spondee and an iamb, were joined together to make a "metron". In Greek and Latin iambic poetry the first syllable of each iambic metron could optionally be long instead of short. An example in Latin is the hymn Aeterne rerum conditor composed in the 4th century by St Ambrose, which begins: "Eternal Creator of (all) things, Who rulest the night and day" The two lines above consist of the following rhythm, and joined together make a tetrameter: | – – u – | – – u – | | – – u – | u – u – | Latin poetry was quantitative, i.e. based on syllable length not stress accent, and in places the word-accent does not match the metrical accent (e.g. and ). In Ambrose's hymn, there is a strong break at the end of each half of the tetrameter, so that it is usual to write the two halves of the verse on separate lines. In early Latin The iambic tetrameter was one of the metres used in the comedies of Plautus and Terence in the early period of Latin literature (2nd century