From this review of the governmental system of Darius we must now return to the actions of his later life.  The history of an Oriental monarchy must always be composed mainly of a series of biographies; for, as the monarch is all in all in such communities, his sayings, doings, and character, not only determine, but constitute, the annals of the State.  In the second period of his reign, that which followed on the time of trouble and disturbance, Darius (as has been already observed) appears to have pursued mainly the arts of peace.  Bent on settling and consolidating his Empire, he set up everywhere the satrapial form of government, organized and established his posts, issued his coinage, watched over the administration of justice, and in various ways exhibited a love of order and method, and a genius for systematic arrangement.  At the same time he devoted considerable attention to ornamental and architectural works, to sculpture, and to literary composition.  He founded the royal palace at Susa, which was the main residence of the later kings.  At Persepolis he certainly erected one very important building; and it is on the whole most probable that he designed—­if he did not live to execute—­the Chehl Minor itself—­the chief of the magnificent structures upon the great central platform.  The massive platform itself, with its grand and stately steps, is certainly of his erection, for it is inscribed with his name.  He gave his works all the solidity and strength that is derivable from the use of huge blocks of a good hard material.  He set the example of ornamenting the stepped approached to a palace with elaborate bas-reliefs.  He designed and caused to be constructed in his own lifetime the rock-tomb at Nakhsh-i-Rustam, in which his remains were afterwards laid.  The rock-sculpture at Behistun was also his work.  In attention to the creation of permanent historical records he excelled all the Persian kings, both before him and after him.  The great Inscription of Behistun has no parallel in ancient times for length, finish, and delicacy of execution, unless it be in Assyria or in Egypt.  The only really historical inscription at Persepolis is one set up by Darius.  He was the only Persian king, except perhaps one, who placed an inscription upon his tomb.  The later monarchs in their records do little more than repeat certain religious phrases and certain forms of self-glorification which occur in the least remarkable inscriptions of their great predecessor.  He alone oversteps those limits, and presents us with geographical notices and narratives of events profoundly interesting to the historian.