Brachot 28 - That day
After the destruction of the Second Temple and of Jerusalem, the Sages were rebuilding the nation. Rabban Gamliel felt that his uncontested authority as a leader was essential to this, and he enforced it by various means.
One of the disagreements was whether the evening prayer is obligatory or voluntary. A certain student posed this question to both Rabbi Yehoshua and Rabban Gamliel, and since they gave different answers, Rabban Gamliel forced Rabbi Yehoshua to stand on his feet all day. Since it was the third time Rabban Gamliel acted in this way, the Sages did not like it, and displaced him and nominated Rabbi Elazar ben Azaria in his place.
On that day many previously unresolved laws were decided, through the testimony of various Sages who were previously not accepted. They added four hundred benches for students (some say, seven hundred), because Rabban Gamliel used to have very strict moral requirements for admittance to the Academy. On seeing this, he became distressed that he withheld Torah from the sons of Israel. They showed him in a dream white ovens with ashes, hinting that the new students were empty inside. However, it was not true - they just wanted to cheer up Rabban Gamliel.
The demoted Rabban Gamliel never absented himself from the Academy, and took part in discussions as equal. In the end he appeased Rabbi Yehoshua, and the Sages, not willing to lower Rabbi Elazar, reinstated Rabban Gamliel to lead for three weeks, and Rabbi Elazar for one week.
Art: Isidor Kaufmann - Portrait of a rabbi