There were few outbreaks among the Indians during this viceroyalty, yet there were troublesome persons among the original tribes of the Chichimecas,--some bands of whom were not yet entirely subjected to the Spanish government,--who contrived to keep up a guerilla warfare, which interrupted the free circulation of the Spaniards through the plains and mountain passes of the Bajio. These were, in all probability, mere predatory attacks; but as it was impossible for the viceroy to spare sufficient numbers of faithful soldiers for the purpose of scouring the hiding places and fastnesses of these robber bands, he resolved to found a number of villages composed of natives and foreigners, and to place in them, permanently, sufficient numbers of troops to protect the adjacent country roads, and to form the nucleus of towns, which, in the course of time, would grow to importance. Such was the origin, by military colonization, of San Felipe Yztlahuaca, and of San Miguel el Grande, now known as Allende, from the hero of that name to whom it gave birth. It was the constant policy of the Emperor to extend the avenues of industry for his emigrant subjects by such a system of security and protection; and, accordingly, Don Francisco Ibarra, was despatched to the interior with orders to explore the northern and western regions, but, on no account, to use arms against the natives except in case of the utmost urgency. Ibarra traversed a wide and nearly unknown region, discovered rich mines of gold and silver, and colonized many places of considerable importance in the subsequent development of Mexico, and among them, the city of Durango, which is now the capital of the state of that name. * * * * * The abdication of Charles V. was unofficially announced in Mexico in 1556; but it was not until the 6th of June of the following year that his successor Philip II. was proclaimed in the capital of New Spain. The policy of the old Emperor was not changed by the accession of the new king; nor does the monarch appear to have influenced in any particular manner the destiny of Mexico during the continuance of Velasco's government, except by the fitting out, at his special command, under the order of his viceroy, of an expedition for the conquest of Florida, which proved disastrous to all concerned in it. Crowds flocked in the year 1558 to the standard raised for this adventure, which it was supposed would result in gratifying the Spanish thirst for gold. In the following year the few who remained of the untoward enterprise, returned with their commanders to Havana and thence to New Spain.