Porson's Law
Porson's Law, or Porson's Bridge, is a metrical law that applies to iambic trimeter, the main spoken metre of Greek tragedy. It does not apply to iambic trimeter in Greek comedy. It was formulated by Richard Porson in his critical edition of Euripides' Hecuba in 1802.[1]
A line of iambic trimeter runs as follows:
- x - u - / x - u - / x - u -
In this scheme, there are three anceps syllables, marked by the symbol x. These may be long or short.
Porson's Law states that, if the third anceps (i.e. the bolded x above) is long and followed by a word break, then it must be a monosyllable.
A simpler summary of the Law is provided in W. W. Goodwin's Greek Grammar:
- "When the tragic trimeter ends in a word forming a cretic (¯ ˘ ¯), this is regularly preceded by a short syllable or by a monosyllable."[2]
M. L. West states it slightly differently, to take account of a rare situation not accounted for by Porson, where the word-break is followed rather than preceded by a monosyllable (e.g. Euripides, Heraclidae 529):
- "When the anceps of the third metron is occupied by a long syllable, this syllable and the one following belong to the same word, unless one of them is a monosyllable."[3]
There are, as West observes, very few breaches of Porson's Law in extant Greek tragedy. When the manuscript tradition, therefore, transmits a line that breaches Porson's Law, this is taken as a reason for suspecting that it may be corrupt.
For example, the first line of Euripides' Ion, as transmitted in the mediaeval manuscript Laurentianus 32.2 (known as "L"), the main source for the play, reads:
- u - u - /u - u - / - - u -
- Ἄτλας, ὁ χαλκέοισι νώτοις οὐρανὸν
- Atlas, who with his back of bronze [rubs up] against heaven... (trans. Lee)
This breaks Porson's Law, because -τοις in νώτοις is long, occurs at the third anceps, and is followed by word break - and therefore Euripides cannot have written it. That the manuscript tradition is incorrect happens to be confirmed by a quotation of this line in a fragmentary papyrus of Philodemus. Philodemus' original text is uncertain, but it is reconstructed by Denys Page to read ὁ χαλκέοισι οὐρανὸν νώτοις Ἄτλας (meaning the same as L's version), which does not break Porson's Law, and therefore may be the correct text. However, other scholars have suggested various other possibilities as to what Euripides may originally have written.[4]