Rabbi Elazar Ben Azariah was a renown leader and scholar, who was elected Nassi (leader) of the Jewish people at the age of eighteen. The Sages feared that as such a young man, he would not be respected. Overnight, his hair turned grey and his beard grew so he looked as if he was 70 years old.
And while we’re trading Yeshiva stories...
Rabbi Elazar Ben Azariah was a renown leader and scholar, who was elected Nassi (leader) of the Jewish people at the age of eighteen. The Sages feared that as such a young man, he would not be respected. Overnight, his hair turned grey and his beard grew so he looked as if he was 70 years old.
http://www.torahtots.com/holidays/pesach/pesseder.htm