A hundred years later,

A hundred years later, Zain-ul-Abidin a grandson of Ali (son of Husain) met as Arab woman at Najaf who told him that her grandmother had helped on the occasion of the birth of Ali. She narrated that according to the account of her grandmother, the child was beautiful, a smile played on his lips, it did not cry like other children, and its birth did not cause any pain to his mother

Source: HOTD