For our Mahdi there are two Signs which have never appeared before since the creation of the heavens and the earth, namely, the moon will be eclipsed on the first night in Ramadhan (i.e., on the first of the nights on which a lunar eclipse can occur) and the sun will be eclipsed on the middle day of Ramadhan (i.e., on the middle one of the days on which a solar eclipse can occur), and these Signs have not appeared since God created the heavens and the earth. (Darqutani, Vol. 1, Part II, page 65)