The motive for the translation was national and linguistic: to bring a Jewish work back from German into Hebrew:
"It is a great sorrow to see that such a book — our book — is written in a foreign tongue, in the German language which most of our people have no need of; and in my zeal I set out, with my feeble powers, to restore the crown to its former glory, and to make it a Hebrew book not only in its content but also in its language." AZR, "Legends of the Tannaim, the Translator's Introduction" (Dvir, 5682/1922); Project Ben-Yehuda.
This is the same zeal for Hebrew that underlies all his work (see "For Hebrew").
AZR portrays Bacher (5610–5674 / 1850–1913) as a giant of the spirit who devoted 25 years to the "Legends of the Tannaim and Amoraim." And what he praises in him is precisely his own ethos of truth:
"And everything he wrote is stamped with the seal of humility and modesty… an investigator who examines and judges freely, keeps far from far-fetched conjectures, and is not ashamed to say at times: I do not know." Ibid. (on Bacher).
This is the same principle AZR formulated in his own historiography (see "AZR the Historian"), and it is the heart of this archive's methodology: a fact only with a source; refraining from conjecture; and saying "I do not know" / "undocumented."
The formative detail in the introduction — when and how the translation was made:
"The first part I translated in the days of the Jaffa expulsion, in Safed and in Tiberias (5677–5678 [1917–1918]), and I thank the Lord who provided me with this work in those days, which was my delight and did not let my spirit sink into the sea of terrors that surrounded us." Ibid. The signature: "Sitting in Jerusalem, on the eve of the New Moon of Tammuz 5679" (1919).
The translation was a spiritual anchor amid the horrors of the expulsion (see "The Jaffa Exile"): while AZR moved between Safed and Tiberias as a refugee, his labor on Bacher was his refuge from the "sea of terrors."