[4] He was descended from a well-known family of scholars, a grandson of Ephraim ha-Kohen[2][5][6] who in turn was the son-in-law of a grandchild of Elijah Ba'al Shem of Chelm.

Upon his return journey he seems to have stayed some time (probably till 1679) at Constantinople where his learning and astuteness made such an impression he became known by the Sephardic title for rabbi, "Chacham", an honorific he retained throughout his life.

In Berlin he married Sarah (died at Lemberg 23 January 1719), the daughter of Meshullam Zalman Mirels Neumark, chief rabbi of Altona, Hamburg, and Wandsbek.

His yeshiva became celebrated, and pupils assembled from all parts to hear him; but his income as rabbi of the Klaus was only 60 thalers annually, so that he was compelled to defray his living expenses by engaging in various business pursuits (e.g. dealing in jewelry).

Friction and strife over religious questions ensued, and finally became so intense that, in 1709, Ashkenazi deemed it advisable to resign and resume his duties as rabbi of the Klaus.

Ashkenazi thought Chayun was an old enemy of his from Sarajevo and Salonica, and at once requested Solomon Ayllon, Chacham of the Portuguese congregation, not to accord patronage to the stranger, who was unfavorably known to him.

Ashkenazi believed himself justified in making this demand, as the Portuguese congregation and its rabbi had, from the beginning, treated him most courteously, and had already, during his term at Altona, repeatedly sent to him from the Sephardim of Hamburg, Amsterdam, and London religio-legal questions for his decision.

Meanwhile, several members of the Portuguese congregation had submitted Chayun's writings to the judgment of Moses Hagiz, a messenger from Jerusalem then sojourning at Amsterdam, who immediately discovered their Sabbatian principles and tendencies and gave the alarm.

He also called the attention of Ashkenazi to the dangerous doctrines published in Chayun's book, whereupon the rabbi again warned the directorate of the Sephardim congregation not to support the author.

Ashkenazi rejected a proposition to designate the objectionable passages, and declined to act as member of a committee of investigation, because he did not regard Ayllon, the rabbi of the Sephardim, as a competent authority on such questions.

[2] The magistrates thereupon sought the opinions of certain professors at Leiden, Utrecht, and Harderwijk, including Willem Surenhuis and Adriaan Reland, on the dispute; but their decision, if given, has not been made known.

[2] Ashkenazi forestalled the magisterial action by resigning his office and fleeing, in the beginning of 1714, from Amsterdam, perhaps secretly, with the aid of his friend Solomon Levi Norden Lima.

After spending two years in Staszów,[8] Poland, he was called to Hamburg to serve as member of a judicial body convened to settle a complicated legal question.

All his contemporaries, even those who knew him only as the head of the Klaus at Altona, unite in praising his profound learning, his astuteness, his clearness of exposition, which never degenerated into the subtleties of the pilpul, and his absolute disregard for the influence of money.