Reb Yitzhak was born to R' Moshe in Datnova, Lithuania in 1880.He
studied in the Volozhin Yeshiva under Rabbi Raphael Shapiro. He also
studied in Slutzk and Kovno. He became the son in law of R.
Chaim-Yirmiyahu Flensberg , Born in 1842, Rabbi in Shakai. R.
Chaim-Yirmiyahu wrote many articles for the Hebrew press. His daughter
Esther, was well educated and a scholar. In 1907, Ester and Yitzhak
had a son in Shaki, they named himYosef ( he changed his last name to
Even-Odem. Yosef became a Doctor. In 1933 he made aliyah to Eretz
Yisrael, published many books on Hebrew terminology of medicine and
nature. –He passed away in 1962.)

While they lived in Kaunas, Rabbi Yitzhak attended a secular school.
He received a diploma after one year.
When he was 26 he was appointed a rabbi of Ganzisk. At age 30 he
became a rabbi in Vilna. He was also a member of the rabbinical Beit
Din. He served the community in Vilna for thirty years. He was very
charismatic. Charming personality and a great speaker and was liked by
both the secular and orthodox Jews. During the First World War he
exhibited his great moral courage and spiritual dedication. He fought
against the anti-Semitic Czarist government .
He was able to prevent the plans of exiling the Jewish population of
Vilna and Warsaw. He also headed the aid society for war victims with
Dr. S. Roisenboim and Dr. Rachmilovitz..
The brief period of Lithuanian rule (27 August –9 September 1920) was
characterized by plans for improvement
in the quality of life of the Jewish residents, including the
appointment of Rabbi Isaac Rubinstein as a local acting minister of
Jewish affairs, the allotment of municipal funds to the Jewish welfare
system, and the plan to
establish a chair for Jewish studies at the local university
Jewish representatives were elected to the Vilna city council.
Following the annexation of Vilna by Poland, a number of the city's
Jews were elected to the Polish Sejm and senate, including Jakub
Wygodski and Yitshak
Rubinstein. Nonetheless, as a result of widespread anti-Semitism in
many segments of Polish society, the 1930s witnessed a gradual decline
in the involvement as well as the degree of influence of Vilna's Jews
in these bodies

In thelate 1920s, "a war" erupted in Vilna. In 1929, when Isaac
Rubinstein was chosen as chief rabbi of Vilna. Grodzinski's supporters
sparked a violent controversy in the community.
The Jewish community of Vilna selected, Rabbi Yitzkak Rubenstein to
be the rabbi of the community and the Gaon Rabbi Chaim Ozer
Grodzinsky, to be his deputy. The government required that Vilna have
a Chief Rabbi. Although Reb Chaim Ozer was a recognized leader of
religious European Jewry, Vilna's official Chief Rabbi was to be
elected by the entire Jewish population, which included a large
secular contingent. Agudath Israel doubted that Reb Chaim Ozer would
be able to command a majority of the total votes, so they joined a
coalition of the Mizrachi, Socialists, and Reformers to elect Rabbi
Rubinstein as a pro-forma head of the Jewish Community, with the
understanding that he would not assert any authority without Reb Chaim
Ozer's approval. After his election, Rabbi Rubinstein's secularist
supporters used this consensus for treating him as the actual Chief
Rabbi of Vilna. In the Yizkor book for "Dotneve" - Jewish Cities,
Towns and Villages in Lithuania until 1918
Dotnuva, Lithuania they wrote;
A well-known Dotnever was R. Yitzhok Rubinshteyn, who was born there
in 1880. He served 30 years as the Rabbi in Kazyon and after 1928 as
the Chief Rabbi of Vilna. He was a well-known, leading personality in
Poland and Lithuania and passed away in 1946 in New York.

Rabbi Rubinstein was the head of the Yavne schools in the Vilna
region. As one of the leaders of the Mizrachi movement he took part in
many Zionists and Jewish congresses as well as multi religion society
for peace.
In the summer of 1939 he was in Switzerland and was planing to go to
America. He changed his mind when the war erupted and after many
difficulties returned to Vilna.After Vilna was taken over by the
Soviets he was able to come to the U.S. in 1940. He was asked to head
Yeshivat Rabbeinu Yitzchak Elchanan (RIETS) (chartered in 1897 as the
Rabbi Isaac Elchanan Theological Seminary New York. He passed away in
1945.