Alphabetical Order

Posted on Wednesday, April 2, 2008.

A reading from the Book of Knuth, Chapter 6:

The use of alphabetic order for entire words seems to be a much later invention; it is something we might think is obvious, yet it has to be taught to children, and at some point in history it was necessary to teach to adults. Several lists from about 300 B.C. have been found on the Aegean Islands, giving the names of people in certain religious cults; these lists have been alphabetized, but only by first letter, thus representing only the first pass of a left-to-right radix sort. Some Greek papyri from the years A.D. 134-135 contain fragments of ledgers that show the names of taxpayers alphabetized by the first two letters. Apollonius Sophista used alphabetical order on the first two letters, and often on subsequent letters, in his lengthy concordance of Homer's poetry (first century A.D.). A few examples of more perfect alphabetization are known, notably Galen's Hippocratic Glosses (c. 200), but they are very rare. Words were arranged by their first letter only in the Etymologiarum of St. Isidorus (c. 630, Book x); and the Corpus Glossary (c. 725) used only the first two letters of each word. The latter two works were perhaps the largest nonnumerical files of data to be compiled during the Middle Ages.

It is not until Giovanni di Genoa's Catholicon (1286) that we find a specific description of true alphabetical order. In his preface, Giovanni explained that

amo		precedes		bibo
abeo		precedes		adeo
amatus		precedes		amor
imprudens		precedes		impudens
iustica		precedes		iustus
polisintheton		precedes		polissenus

(thereby giving examples of situations in which the ordering is determined by the 1st, 2nd, ..., 6th letters), “and so on in like manner.” He remarked that strenuous effort was required to device these rules. “I beg of you, therefore, good reader, do not scorn this great labor of mine and this order as something worthless.”

A detailed study of the development of alphabetic order, up to the time printing was invented, has been made by Lloyd W. Daly [Collection Latomus 90 (1967), 100 pages]. He found some interesting old manuscripts that were evidently used as worksheets while sorting words by their first letters (see pages 89-90 of his monograph).

The first dictionary of English, Robert Cawdrey's Table Alphabeticall (London, 1604), contains the following instructions:

Nowe if the word, which thou art desirous to finde, beginne with (a) then looke in the beginning of this Table, but if with (v) looke toward the end. Again, if they word beginne with (ca) looke in the beginning of the letter (c) but if with (cu) then looke toward the end of that letter. And so on of all the rest. &c.

Cawdrey seems to have been teaching himself how to alphabetize as he prepared his dictionary; numerous misplaced words appear on the first few pages, but the alphabetic order in the last part is not as bad.

Volume 3 / Sorting and Searching, 2nd Ed., p. 421

I've written before about how thinking recursively, something most of us take for granted, is in fact something that must be taught (or discovered). I wonder if alphabetical order took so long to catch on because it is a recursive procedure.