His travels and mercantile experience had led E t u eopre him to conclude that the Hindu methods of computing were in advance of those then in general use, and in 1202 he published his Liber Abaci, which treats of both algebra and arithmetic. In this work, which is of great historical interest, since it was published about two centuries before the art of printing was discovered, he adopts the Arabic notation for numbers, and solves many problems, both arithmetical and algebraical.
If then Aristotle was for some thirty-five years gradually and simultaneously composing manuscript discourses into treatises and treatises into a system, he was pursuing a process which solves beforehand the very difficulties which have since been found in his writings.
The problems of the relations of the life of the State and the life of the individual, which Aristotle ever suggests and never solves, are problems with which the Christian Church has at least attempted to deal."
This problem he here solves for the first time, with the help of an Italian example: at least his design so closely repeats that of Leonardo da Vinci's famous and early destroyed equestrian statue of Francesco Sforza that we must certainly suppose him to have seen either the model itself or such a drawing of it as is still preserved byLeonardo's own hand.
In general we may say then that the Trinity takes on four differing aspects in the Christian church: in its more common and easily apprehended form as three Gods, in its ecclesiastical form as a mystery which is above reason to be accepted by faith, in its philosophic form as the highest reason which solves the ultimate problems of the universe, and finally, as a mode by which the spirit through an emotional content enters into communion with God himself.