 Decans were connected, for example, with various diseases and with the timing for the engraving of talismans for curing them; with decanic "faces" (or "phases"), a system where three decans are assigned to each zodiacal sign, each covering 10° of the zodiac, and each ruled by a planetary ruler (see below); and correlated with astrological signs.Decans are named in various Greco-Egyptian sources, many Hermetic writings, the Testament of Solomon, and the writings of Aristobulus of Paneas.Julius Firmicus Maternus, Cosmas of Maiuma, Joseph Justus Scaliger, and Athanasius Kircher.