Nathan (born about 1035 and died in 1106) was an itinerant vendor of linen wares in his youth. He belonged to the family Degli Mansi, an Italian rendering of the Hebrew _Anaw_ or _Meek_. The latter is still a rare but familiar Jewish surname. Legend has it that the founder of the Degli Mansi house was one of the original settlers introduced into Rome by Titus. At all events, the family had a long record of literary fame. Like many another merchant-traveller of the Middle Ages, Nathan made use of his earlier wanderings (as he did of his later journeys), to sit at the feet of all the Gamaliels of his age. Many and various were his teachers. He abandoned business when he returned to Rome after his father’s death. He tells us how he made the arrangements for the interment, and here straightway we perceive that his _Aruk_ is no ordinary dictionary. For in the poem, which he appends as a kind of retrospective preface, he records how sternly he had ever disapproved of the expenses incurred at Jewish funerals in his time. Protests were vain, but example was more fruitful. In place of the double cerements in common use, he laid his father in his tomb with a single shroud. This, he records, became the model for others to imitate. Death was a frequent visitor in his abode. Of his four sons, none survived the eighth year, one not even his eighth day. Grief did not crush him. “I found sorrow and trouble, then I called on the name of the Lord,” he quotes. He proceeded to erect a house of another kind. Not of flesh and blood, but vital with the spirit of Judaism, his _Aruk_ is a monument more lasting than ten children. In what, then, does the importance of the dictionary consist? It is, of course, primarily, what Graetz terms it, “a key to the Talmud.” No doubt there were earlier compilations of a similar nature, but Nathan’s book was the most renowned of its own age, and became the basis of every subsequent lexicon to the Talmud. Gentile and Jew, from Buxtorf to Dalman and from Musafia to Jastrow, employed it as the ground-work of their own lexicographical research. Moreover, it was again and again edited and enlarged; but we are not dealing here with bibliographical details. Suffice it to mention the final edition by Alexander Kohut. Kohut began his _Aruch Completum_ while a European Rabbi in 1878, and finished it in New York in 1892. It is remarkable that two of the best modern lexicons to the Talmud (Kohut’s in Hebrew and Jastrow’s in English) both emanate from America.