What do Ibn al-Shatir and Ibn Tufail have in common?
Ibn al-Shatir Ibn al-Shatir or Ibn ash-Shatir (Arabic: ابن الشاطر‎ ‎ ; 1304–1375) was an Arab astronomer. He worked as "muwaqqit" (موقت, religious timekeeper) in the Umayyad Mosque in Damascus and constructed a sundial for its minaret in 1371/72.
Al-Abbas ibn Ahmad ibn Tulun Al-ʿAbbās ibn Aḥmad ibn Ṭūlūn was the eldest son of the founder of the Tulunid dynasty, Ahmad ibn Tulun, and heir-apparent until his failed attempt to usurp his father in 879. After a failed attempt to take over Ifriqiya, he was imprisoned in Egypt and executed shortly after the succession of his brother, Khumarawayh, in May 884.