Two hundred years had now elapsed since Gouvea called attention to the ruins of Persepolis. A considerable amount of literature had accumulated on the subject, and large numbers of plans and drawings of the principal objects were taken, which materially assisted the student. On looking back over these, however, it was curious to observe how widely the descriptions differed from each other, and how irreconcilable were the various views of the same monument. The explanation was not far to seek. Most of the travellers could only spare a few days from more pressing occupations to devote to the work. They were afterwards compelled to complete from memory the hasty sketches they had made on the spot, and although many of them display considerable skill in the use of their pencil, only a few had any professional knowledge of drawing. They were, moreover, all alike at the mercy of the engraver, and some thought they had good reason to complain of the treatment they received at his hands. But there was another cause that led to inevitable discrepancies. Few of them aimed to produce the minute accuracy of a photograph, or could resist the temptation of idealising the work before them: on the one hand, Le Bruyn exaggerated the ruin wrought by time; on the other, Niebuhr repaired its ravages. According to the one, the sculptured staircase is a confused mass of mutilated figures; according to the other, it appears as perfect as when first completed by the sculptor. Nor was it only in the drawings that inaccuracies were to be detected. The measuring tape itself seemed to yield different results in different hands. It was impossible to find agreement even as to the number of steps in the great staircase. According to one, there were only ninety-five (Herbert); according to another, one hundred and thirteen (Kaempfer); and other accounts ranged between these two extremes.