The details of Nathan's sad life must be excerpted and pieced together from several autobiographic verses appended to the first edition of his lexicon. It appears that he had begun life not as a student, but as a peddler of linen wares, which was then considered a distasteful occupation.
The death of his employer caused him to abandon trade for the Torah. He returned home, where his father began to bestow upon him the treasures of learning, the accumulation of which was continued under foreign masters.
First, Nathan went to Sicily, whither Matzliach ibn al-Batzaq had just returned from a course of study under Hai Gaon, the last of the Pumbedita geonim. It was there that Nathan garnered that Babylonian learning which has led some to the erroneous notion that he had himself pilgrimed to Pumbedita.
Then Narbonne enticed him, where he sat under the prominent exegete and haggadist R. Moses ha-Darshan. On his way home he probably lingered for a while at the several academies flourishing in Italy, notably at Pavia, where a certain R. Moses was head master, and at Bari, where R. Moses Kalfo taught. He arrived home, however, from his scholarly travels some time before the death of his father, which occurred about the year 1070, and which gave him the opportunity of illustrating the simplicity of funeral rites which he had been advocating.
The presidency of the rabbinic college was thereupon entrusted by the Roman community to Jehiel's three learned sons: Daniel, Nathan, and Abraham – "the geonim of the house of R. Jehiel," as they were styled (Shibbole ha-Leḳeṭ, ii. 5). Daniel, the eldest, seems to have composed a commentary on the mishnaic section Zera'im, from which the "'Arukh" quotes frequently, and to have stood in friendly relations with Christian scholars. The three brothers rapidly acquired general recognition as authorities on the Torah; and numerous inquiries were addressed to them. Their most frequent correspondent was R. Solomon ben Isaac (Yiẓḥaḳi), an Italian scholar who is not to be identified with Rashi.
Nathan's private life was extremely sad. All his children died very young; and the bereaved father sought solace in philanthropy and scholarly application. In the year 1085 he built a communal bathhouse conforming to the ritual law; and about seventeen years later, Sept., 1101, he and his brothers erected a beautiful synagogue. In February of the latter year had been completed his magnum opus – the Arukh.
The sources of this work are numerous. Aside from the Arukh of Tzemach ben Paltzoi (Ẓemaḥ b. Palṭoi), which he utilized (it should be stated, however, that Rapoport and Geiger deny this), he used a very large number of additional works. Above all, he placed under contribution the information received, in both oral and written form, from R. Maẓliaḥ and R. Moses ha-Darshan, the former of whom, in particular, through his studies under Hai, had made himself the repository of Eastern learning. The entire extent of Nathan's indebtedness to his authorities can not be estimated, for the reason that of the hundreds of books cited by him many have not been preserved. But none will deny his obligation to R. Gershom of Mainz, whom he repeatedly quotes, though, as Kohut rightly maintains against Rapoport, he can not have been his personal disciple.
Similarly he used the writings of R. Hananeel b. Chushiel and R. Nissim ben Jacob, both living at Kairwan. So frequent, in fact, were the references to R. Hananeel in the lexicon that R. Jacob Tam, for example, regarded the work as based entirely on the commentaries of that author (Sefer ha-Yashar, p. 525), while the author of the Or Zarua, as a matter of course, referred to him almost all of the lexicon's anonymous statements.
Hai Gaon, again, figures very frequently in its pages, sometimes simply designated as "the Gaon," while it has particularly assimilated all philologic material that is contained in his commentary on the mishnaic order Ṭohorot.
Since the structure of the Arukh consists, as it were, of so many bricks, it is hard to decide whether the builder really possessed all the linguistic learning stored up in it. None can gainsay the author's philologic spirit of inquiry – quite remarkable for his day, which antedated the science of linguistics; his frequent collation of "variæ lectiones" is notable, while his fine literary sense often saved him from crude etymological errancies.
But, withal, the multitude of languages marshaled in the Arukh is prodigious even for a period of poly-glot proclivities. The non-Jewish Aramaic dialects are encountered side by side with Arabic, Persian, Greek, Latin, and even Slavonic, while Italian seems as familiar to the author as the various rabbinic forms of style.
This multiplicity of languages, however, is at present generally considered a mere mark of the multifarious character of the compilation; and the credit for the exegetic employment of the several languages is given to Nathan's authorities rather than to himself.
While he possessed, no doubt, a superficial and empiric knowledge of Latin and Greek, of which the former already contained an admixture of contemporary Italian, and the latter, subdivided into spoken and written Greek, was still partly used in southern Italy; while he may have acquired a desultory acquaintance with Arabic, and certainly was quite familiar with Italian, yet it may be stated almost with certainty that the majority of his etymologies were compiled and copied from his various source-books.
For this reason, perhaps, the various dialects appear in the Arukh under several names, each originating seemingly in a different author, as Arabic, for example, which occurs under three distinct denotations, possibly without Nathan being aware of their synonymity. To the same cause may be assigned the polyonymy of the Hebrew and rabbinic dialects in the Arukh, as well as the presence of a great deal of geographic and ethnographic information which the author certainly did not acquire in actual travel. As regards the grammatical derivation of Hebrew words, Nathan deviated from the principle of triliteral roots discovered by Judah ben David Chayyuj (Ḥayyuj) and adopted by the Spanish grammarians as a rule; like the majority of French and German rabbis, he considered two letters, and at times one, sufficient to form a Hebrew root.
The Arukh is significant as a monument in the history of culture. Aside from its purely scientific value as a storehouse of old readings and interpretations as well as of titles of many lost books, it is important as the only literary production of the Italian Jews of that age. Moreover, though mainly a compilation, it is one of the most noteworthy medieval monuments of learning. Compiled at the historic juncture when Jewish scholarship was transplanted from Babylonia and northern Africa to Europe and was subject to the perils of aberration, it signally emphasized the necessity of preserving the old rabbinical treasures and traditions. Its service in this respect was equivalent to that rendered by the two great products of contemporary Spanish and French Jews – Alfasi's Talmudic code and Rashi's commentary. Together the three contributed toward the spread of rabbinic study. Besides, one has to depend upon the Arukh for whatever knowledge one may have of the intellectual condition of the Italian Jews in the 11th-century. Since its author, for example, uses the Italian language freely to elucidate etymologies, that he frequently offers the vernacular nomenclature for objects of natural history, that he repeatedly calls into service for purposes of illustration the customs of foreign peoples, the character of the reading public of his day can easily be inferred. The dawn of skepticism may be discerned in his remark that as regards conjuring and amulets neither their grounds nor their sources were known (Aruch Completum, vii. 157, s.v.).
The Arukh rapidly achieved a wide circulation. According to Kohut, even Rashi was already in a position to utilize it in the second edition of his commentaries, having been acquainted with it by R. Kalonymus ben Shabbethai, the noted rabbi who had moved to Worms from Rome. Kalonymus, however, can at best have transported to his new home but meager information concerning the Arukh, as his removal occurred about thirty years prior to its completion; the first folios he may well have seen, since he was intimately acquainted with Nathan. A generation after the time of Rashi the Arukh is found in general use among the Biblical commentators and the tosafists, as well as among the legalistic and the grammatical authors. Numerous manuscript copies were brought into circulation; and with the introduction of printing its spread was widely extended.
The first edition, which bears neither the date nor the place of publication, probably belongs to the year 1477, while in 1531 Daniel Bomberg of Venice issued what is no doubt the best of the early editions. In both the copying and the printing processes, however, the work suffered innumerable alterations and mutilations, which have been recently repaired to a certain extent by the scientific edition issued, on the basis of the first editions and of seven manuscripts, by Alexander Kohut (Aruch Completum, 8 vols. and supplement, Vienna and New York, 1878–92).
A further proof of the popularity gained by the Arukh lies in the numerous supplements and compendiums which soon commenced to cluster about it. Down to recent times all rabbinic lexicons have been grounded on the Arukh. The first supplement was written in the 12th century by R. Samuel ben Jacob ibn Jam'i or Jama' (J. Q. R. x. 514) of Narbonne, under the title Agur (edited by Solomon Buber in Grätz Jubelschrift, Hebr. part, pp. 1–47), a small work of little significance.
In the 13th-century R. Tanchum ben Joseph of Jerusalem wrote a lexicon, Al-Murshid al-Kafi, which purposed not only to replace the Arukh, which had grown rare, but also to complete and to correct it.
Abraham Zacuto, author of the Yuḥasin, at the beginning of the sixteenth century composed a supplement entitled Iḳḳere ha-Talmud, of which only a fragment of the latter part has come down. About the same time Sanctus Pagninus, a Christian, issued an Enchiridion Expositionis Vocabulorum Haruch, Thargum, Midraschim Rabboth, et Aliorum Librorum (Rome, 1523; Steinschneider, Cat. Bodl. col. 2083). The general method of the Arukh was also adopted by Elijah Levita, who, in his Meturgeman and Tishbi, advanced a step in that he differentiated the targumic and the Talmudic words and also sought to complete his prototype.
The manner and the matter of the Arukh were closely followed by Johannes Buxtorf in his Lexicon Chaldaicum Talmudicum (Basel, 1639), and by David de Pomis in his Ẓemaḥ Dawid. Early in the seventeenth century Menahem Lonzano issued his small but useful supplement, Ma'arik, concerned particularly with foreign words (in Shete Yadot, Venice, 1618; newly edited by Jellinek, Leipzig, 1853). Ma'arik ha-Ma'areket, a compilation by Philippe d'Aquin, appeared in Paris in 1629.
No doubt the best supplements to the Arukh were written in the same century by Benjamin Musaphia, a physician at Hamburg, and by David ha-Kohen de Lara. Mussafia's Musaf he-'Arukh (1655), probably known also as Arukh he-Ḥadash, according to Immanuel Löw, devoted itself particularly to the Greek and Latin derivatives, leaning largely on Buxtorf. De Lara (d. 1674) published Keter Kehunnah (Hamburg, 1668), in which he had set before himself polyglot purposes, and which, though brought down to "resh," was published only as far as the letter "yod" (Steinschneider, l.c. col. 875). His smaller work, on the other hand, Ir Dawid (Amsterdam, 1638), of which the second part was called Meẓudat Ẓiyyon, confined itself almost exclusively to Greek derivatives.
Even the nineteenth century witnessed the publication of several works accredited to the classic lexicon. Isaiah Berlin (d. 1799) wrote Hafla'ah Sheba-'Arakhin (Breslau, 1830; Vienna, 1859; Lublin, 1883), annotations to the Arukh; similar notes were appended by I. M. Landau to his unscientific edition of the Arukh (5 vols., Prague, 1819–40); while S. Lindermann has issued elucidations under the title Sarid ba-'Arakhin (Thorn, 1870).
Besides, there are several anonymous dictionaries attached to the same classic, e.g., the abbreviated Arukh, Arukh ha-Ḳaẓer, known also as Ḳiẓẓur 'Arukh, which was successively printed at Constantinople (1511), Cracow (1591), and Prague (1707), and which contains merely the explanation of words, without their etymologies.
Another short Arukh, frequently cited by Buxtorf, and discovered in a manuscript at Bern, has been found to contain numerous French and German annotations. Of such epitomes there has no doubt been a multitude in manuscript form. A dictionary of still wider scope than the Arukh is the Sefer Meliẓah of Solomon ben Samuel. Solomon Marcus Schiller-Szinessy, in fine, records the existence of a Lexicon of the Difficult Words in the Talmud (Cat. Cambridge, p. 114).