The greater part of his troops were in Rei with his son al-Mandi, who had conquered Tabaristan, in Africa, with Mahommed b.
The dictator appointed to meet the dangers of war, sedition or crime was technically described as " the administrative dictator (rei gerundae causa).
The only complete translation is Il Libro dei Rei, by I.
Thus in the 5th century, among the comites attached to the emperor's establishment, we find, e.g., the comes sacrarum largitionum and the comes rei privatae; while others, forming the council, were styled comites consistorii.
The name l'arte magiore, the greater art, is designed to distinguish it from l'arte minore, the lesser art, a term which he applied to the modern arithmetic. His second variant, la regula de la cosa, the rule of the thing or unknown quantity, appears to have been in common use in Italy, and the word cosa was preserved for several centuries in the forms toss or algebra, cossic or algebraic, cossist or algebraist, &c. Other Italian writers termed it the Regula rei et census, the rule of the thing and the product, or the root and the square.
