Princely Pandect on Astronomy

Subsequently T?u¯si was to pen hisown commentary on the work (the ?all-i Mushkilat-i Mu?iniya, or A solution to the difficulties of the Mu?iniya) and he used this occasion to discuss his celebrated mathematical formulation “the T?u¯si Couple” (a concept that he merely hinted at in the Risala-yi Mu?iniya).