"But still they marched, seeing in one place a white woman with a painted chin, and in another a wild hailstorm. The stones, as big as oranges, dented armor and killed animals. Trembling, the people wept and prayed and made vows. Each day they heard how far they had gone according to the soldier whose duty it was to count steps by which the leagues could be computed. In all that wilderness they were appalled at how little mark so great a throng of men and women and beasts made on the grass upon the plain. They left no trail, for the grass in the wind waved over their path like the sea in a galleon's wake."
Imagine, if you will, that being your job, to compute the passing leagues by counting steps. Then imagine that the leagues had to be computed from the time you left Mexico City until the Llano Estacado had been explored and maybe all of the way back again. Would the General, Francisco Vasquez de Coronado, have one man do this, or alternate the tedious and boring job? It had to be done, there was no easier way at the time of measuring distance on flat land. But you had to do it if you wanted to get back. They realized they would die of thirst if they got lost.
No pedometer, no odometer, no GPS to mark the distance in a flat and grass covered land. It had to be done by some other method. The counter could not often lose count or he literally would have lost not only those who he was with, but eventually he would lose his head.