But of the arithmetical art, which by composition contains philosophy, number became a first principle, which is an indefinable and incomprehensible (entity), comprising in itself all the numbers that can go on ad infinitum by aggregation. But the first monad became a principle, according to substance, of the numbers, which (principle) is a male monad, pro-creating paternally all the rest of the numbers. Secondly, the duad is a female number, which by the arithmeticians is also itself denominated even. Thirdly, the triad is a male number; this also it has been the usual custom of arithmeticians to style odd. In addition to all these, the tetrad is a female number; and this same, because it is feminine, is likewise denominated even. All the numbers therefore, taken generically, are four—number, however, as regards genus, is indefinite—from which, according to their system, is formed the perfect number—I mean the decade. For one, two, three, four, become ten—as has been previously proved—if the proper denomination be preserved, according to substance, for each of the numbers. This is the sacred quaternion, according to Pythagoras, having in itself roots of an endless nature, that is, all other numbers; for eleven, and twelve, and the rest, derive the principle of generation from the ten. Of this decade—the perfect number—there are called four parts—number, monad, power, cube—whose connections and mixtures take place for the generation of increase, according to nature completing the productive number. For when the square is multiplied into itself, it becomes a biquadratic; but when the square is multiplied into a cube, it becomes the product of a quadratic and cube; but when a cube is multiplied into a cube, it becomes the product of cube multiplied by cube. Wherefore all the numbers are seven; so that the generation of things produced may be from the hebdomad—which is number, monad, power, cube, biquadratic, product of quadratic multiplied by cube, product of cube multiplied by cube.