The backbone of the military power in the seventh century was the militia, some six hundred units of an average of a thousand men, recruited from the general farming population for short-term service: one month in five in the areas close to the capital. These men formed a part of the emperor's guards and were under the command of members of the Shensi gentry. This system which had its direct parallels in the Han time and evolved out of a Toba system, broke down when short offensive wars were no longer fought. Other imperial guards were staffed with young sons of the gentry who were stationed in the most delicate parts of the palaces. The emperor T'ai-tsung had his personal bodyguard, a part of his own army of conquest, consisting of his former bondsmen (_pu-ch'ü_). The ranks of the Army of conquest were later filled by descendants of the original soldiers and by orphans. In the provinces, the armies of the military prefectures gradually lost their importance when wars became longer and militiamen proved insufficient. Many of the soldiers here were convicts and exiles. It is interesting to note that the title of the commander of these armies, _tu-tu_, in the fourth century meant a commander in the church-Taoist organization; it was used by the Toba and from the seventh century on became widely accepted as title among the Uigurs, Tibetans, Sogdians, Turks and Khotanese. When the prefectural armies and the militia forces weakened, special regional armies were created (from 678 on); this institution had existed among the Toba, but they had greatly reduced these armies after 500. The commanders of these new T'ang armies soon became more important than the civil administrators, because they commanded a number of districts making up a whole province. This assured a better functioning of the military machine, but put the governors-general in a position to pursue a policy of their own, even against the central government. In addition to this, the financial administration of their commands was put under them, whereas in the past it had been in the hands of the civil administration of the various provinces. The civil administration was also reorganized (see the table on pages 83-84).