"If not now, when?" is a commonly used phrase and is also the title of a book by Primo Levi and an album by Incbus. The phrase is a shortening of a quote by Hillel "If I am not for myself who is for me? And being for my own self, what am 'I'? And if not now, when?". Hillel (born Babylon traditionally c. 110 BCE, died 10 CE in Jerusalem) was a famous Jewish religious leader and one of the most important figures in Jewish history. He is associated with the development of the Mishnah and the Talmud. Renowned within Judaism as a sage and scholar, he was the founder of the House of Hillel school for Tannaïm (Sages of the Mishnah) and the founder of a dynasty of Sages who stood at the head of the Jews living in the land of Israel until roughly the fifth century of the Common Era.