Sulayman Solong stands on the threshold between legend and recorded history: he is the first Keira ruler of whom historians speak with confidence, remembered as the founder of the sultanate proper and the sovereign who made Islam its official religion, building mosques and encouraging observances such as circumcision. His Fur epithet Solongdungo, 'the Arab' or 'the red', is explained both by a ruddy complexion and by his claimed descent from the stranger-ancestor Ahmad al-Maqur, tying the Muslim king back into the older charter of the wandering Arab. Around his person cluster the sacred emblems of Keira kingship, above all the copper kettledrums, the nahas, sounded at the yearly festival that renewed the sultan's authority. His reign dates are uncertain: some traditions place him around 1596 to 1637, while a number of modern scholars argue for a later floruit toward 1660 to 1680.