Isopsephy

Isopsephy (ˈaɪsəpˌsɛfi; ἴσος isos meaning "equal" and ψῆφος psephos meaning "pebble") or isopsephism is the practice of adding up the number values of the letters in a word to form a single number. The total number is then used as a metaphorical bridge to other words evaluating the equal number, which satisfies isos or "equal" in the term. The early Greeks used pebbles arranged in patterns to learn arithmetic and geometry, which corresponds to psephos or "pebble" and "counting" in the term. Isopsephy is related to gematria: the same practice using the Hebrew alphabet. It is also related to the ancient number systems of many other peoples (for the Arabic alphabet version, see Abjad numerals). A gematria of Latin script languages was also popular in Europe from the Middle Ages to the Renaissance, and its legacy remains in code-breaking, numerology, and Masonic symbolism today (see arithmancy). Until Arabic numerals were adopted and adapted from Indian numerals in the 8th and 9th centuries AD, and promoted in Europe by Fibonacci of Pisa with his 1202 book Liber Abaci, numerals were predominantly alphabetical. For instance in Ancient Greece, Greek numerals used the alphabet. It is just a short step from using letters of the alphabet in everyday arithmetic and mathematics to seeing numbers in words, and to writing with an awareness of the numerical dimension of words. An early reference to isopsephy, albeit of more-than-usual sophistication (employing multiplication rather than addition), is from the mathematician Apollonius of Perga, writing in the 3rd century BC. He asks: "Given the verse: ΑΡΤΕΜΙΔΟΣ ΚΛΕΙΤΕ ΚΡΑΤΟΣ ΕΞΟΧΟΝ ΕΝΝΕΑ ΚΟΥΡΑΙ ('Nine maidens, praise the glorious power of Artemis'), what does the product of all its elements equal?" More conventional are the instances of isopsephy found in graffiti at Pompeii, dating from around 79 AD. One reads Φιλω ης αριθμος φμε, "I love her whose number is 545." Another says, "Amerimnus thought upon his lady Harmonia for good. The number of her honorable name is 45.