Ibn Khordadbeh, he is a historian and geographer born 820-912) is known for his Kitabul Masalik wal Mamalik (كتابالمسالكوالممالك, "The Book of Roads and Kingdoms"). In the book Ibn Khordadbeh describe the distance between countries through which the Muslim world trade lane, which he worked during working under the Abbasid Caliph Al Ma'mun. He also stated explicitly that the earth is round like a ball, and placed in the middle of the sky room "like the yellow of an egg
