Cancer (constellation) for Karkinos's effort, gave it a place in the sky. Some scholars have suggested that Karkinos was a late addition to the myth of Hercules in order to make the Twelve Labors correspond to the twelve signs of the Zodiac. , the Sun appears in the constellation Cancer from July 20 to August 9. In tropical astrology, the Sun is considered to be in the sign Cancer from June 21 to July 22, and in sidereal astrology, from July 16 to August 16. This constellation can be found during winter or autumn. In Chinese astronomy, the stars of Cancer lie
Leo the Mathematician from the caliph to the Byzantine emperor Theophilos, who, impressed by his international repute, conferred on him a school ("ekpaideutērion") in either the Magnaura or the church of the Forty Martyrs. In the version of the story recorded by Theophanes Continuatus, the caliph, upon receiving Leo's letter of refusal, sent a letter requesting answers to some difficult questions of geometry and astrology, which Leo obliged. Al-Mamun then offered two thousands pounds of gold and a perpetual peace to Theophilos, if only he could borrow Leo's services briefly; the request was declined. The emperor then honoured Leo by having John the