About this time, 1537–38, Friar Juan de la Asuncion seems to have visited the inland tribes north of the Spanish settlements. Mr Bandelier has presented all the evidence obtainable regarding the labors of this friar.[19] The most probable interpretation of the statements which refer to his wanderings is that Friar Juan went alone and without official assistance, and that he may have traveled as far north as the river Gila. The details of his journey are hopelessly confused. It is more than probable that there were a number of friars at work among the outlying Indian tribes, and there is no reason why one or more of them may not have wandered north for a considerable distance. During the same year the viceroy made an attempt, possibly in person, to penetrate into the country of Topira or Topia, in northwestern Durango,[20] but the mountains and the absence of provisions forced the party to return. It may be that this fruitless expedition was the same as that in which, according to Castañeda, Coronado took part, while Friar Marcos was on his way to Cibola. It is not unlikely, also, [p354] that Friar Marcos may have made a preliminary trip toward the north, during the same year, although this is hardly more than a guess to explain statements, made by the old chroniclers, which we can not understand. As yet nothing had been found to verify the reports brought by Cabeza de Vaca, which, by themselves, were hardly sufficient to justify the equipment of an expedition on a large scale. But Mendoza was bent on discovering what lay beyond the northern mountains. He still had the negro Estevan, whom he had purchased of Dorantes, besides a number of Indians who had followed Cabeza de Vaca to Mexico and had been trained there to serve as interpreters. The experience which the negro had gained during the years he lived among the savages made him invaluable as a guide. He was used to dealing with the Indians, knew something of their languages, and was practiced in the all-important sign manual.