When Letters Are Numbers

For most of history, people who wrote in Hebrew, Greek or Arabic did not use separate digits. They counted with their alphabets. Each of the first nine letters stood for the units 1 to 9, the next nine for the tens, and the next for the hundreds, so that any number could be spelled out in letters. The order came from the ancient Phoenician alphabet, which is why the three systems line up so closely at the start.

Value	Hebrew	Greek	Arabic (abjad order)
1	alef א	alpha Α	alif ا
2	bet ב	beta Β	ba ب
3	gimel ג	gamma Γ	jim ج
4	dalet ד	delta Δ	dal د
5	he ה	epsilon Ε	ha ه
6	vav ו	digamma Ϝ	waw و
7	zayin ז	zeta Ζ	zay ز
8	het ח	eta Η	ḥa ح
9	tet ט	theta Θ	ṭa ط
10	yod י	iota Ι	ya ي

The Greek list includes digamma, a letter that had dropped out of the written language but was kept as the numeral 6. The Arabic list follows the old order, remembered by the nonsense words abjad hawwaz, not the modern dictionary order. Because letters were numbers, every word had a value, and that simple fact invited readers to compare words with equal totals.

In Judaism the practice is called gematria, probably from the Greek geometria. Rabbinic literature lists it among the accepted methods of interpretation, though always as a supporting argument rather than proof. The Talmud observes that Abraham went to war with 318 servants, and that the name of his steward Eliezer also totals 318; perhaps, it suggests, Eliezer alone went with him. Another saying links yayin, “wine”, and sod, “secret”, both worth 70: when wine goes in, secrets come out. Medieval Kabbalists, above all Abraham Abulafia in the thirteenth century, made letter combinations and their values central to mystical meditation. In everyday Jewish life the word chai, “alive”, worth 18, makes 18 a lucky number for gifts.

The Greeks called the same game isopsephy. It was often playful: a graffito from Pompeii, buried in 79 CE, declares love for a girl “whose number is 545”. It could also be political. The historian Suetonius records that after Nero’s mother died, Romans circulated a line noting that the Greek name Nero had the same value as the phrase “killed his own mother”. Christians took up the method early. The Sibylline Oracles give the name Iesous the value 888, which some writers contrasted with the 666 of the beast in Revelation.

In the Islamic world the abjad values became a tool of poets and mystics. Persian, Ottoman and Urdu poets composed lines whose letters added up to the year of a building, a birth or a death, a form of chronogram called tarikh. Sufi writers explored the “science of letters” as a way of contemplating the divine names. In South Asia, 786, the value of the Qur’an’s opening phrase, is commonly written at the top of letters, though some scholars discourage it. In the nineteenth century the Babi and Baha’i faiths built on the same system: Baha, “glory”, is worth 9, and wahid, “one”, is worth 19, the basis of their calendar.

India took another path. Having developed place-value digits with a zero, Indian scholars did not need letters as everyday numerals. They needed them for memory, because astronomy and mathematics were taught in verse. In the katapayadi system, attested especially in Kerala from the later first millennium CE, each consonant stands for a digit from 0 to 9, and vowels following a consonant count for nothing, so a long table of numbers could become a line of poetry. Digits were usually read in reverse order, from the units up. The same system later gave the names of the 72 parent ragas of Carnatic music, whose first syllables encode their place in the list.

The Pythagoreans of ancient Greece did not use letter values in this way, but they gave the idea of meaningful number its philosophical depth. From the sixth century BCE, followers of Pythagoras taught that the cosmos is ordered by number, partly because musical harmonies follow simple ratios such as 2:1 and 3:2. They revered the tetraktys, a triangle of ten dots arranged 1, 2, 3, 4, and gave numbers moral meanings, such as justice for four. Plato, the Neoplatonists and medieval Christian writers inherited this outlook.

Latin Europe, whose Roman numerals were already letters, found its own game in the chronogram. From the late Middle Ages, and especially in the sixteenth to eighteenth centuries, inscriptions on churches, coins and title pages capitalised the letters I, V, X, L, C, D and M so that they summed to a year. A phrase such as ChrIstVs DuX ergo trIVMphVs, “Christ the leader, therefore triumphant”, yields 1627. Like gematria and abjad, it was a way of showing that words and history could be woven together with skill. That is what these systems record: centuries of careful, inventive reading, not a hidden code behind the world.