Note 1 — VOLUME VI slice I Châtelet to Chicago (continued 9)
Reading edition
The earliest known problem is ascribed to an Arabian caliph of the 9th century. The first known collection is in a manuscript (in the British Museum) of King Alphonso of Castile, dated 1250; it contains 103 problems. The collection of Nicolas of Lombardy, dated 1300, comprises 192 problems.