Neil Rosenstein has the birth date as 1774. Nathan was the A.B.D. (Av Beit Din - Head of the Rabbinical Court) of Lubartow.

"While the rest of the family adopted the surname of Berenstein, he took the name Lewenstein, after his grandfather (i.e. Leib = Lev / Lew)."

(The Unbroken Chain", Neil Rosenstein, Ch IV, Pg 247)

Birth and death data taken from the records on Lublin in the following website: http://data.jewishgen.org/wconnect/wc.dll?jg~jgsys~jripllat2

(Natan was a widower when he died.)

הרב ר' נתן לעווינשטיין אבד"ק לעווערטוב . נולד בשנת תקל"ד ונפטר בשם טוב בעיר לובלין ביום ב' ד' באלול תקצ"ד לפ"ק -------------------- A lawyer in Lvov

Nathan was born in 1774, A.B.D. Lubartow, and died in Lublin 1834. He was the son of R' Issachar Berish, the son of R' Aryey Leib, son of Pnei Yehoshua.

While the rest of the family adopted the surname of Berenstrin, he took the name of Levinstein, after his grandfather (ie. Leib = Lev/Lew).

Nathan's mother was Gitel, the daughter of R' Isaac Hamburger Horowitz (Chapter XV1 - Introduction)

Source

The Unbroken Chain - Neil Rosenstein (1990) Volume 1, Chapter 1V, page 248, G 14