View looking north, down the staircase on the northern slope of the Herodium from the area of the reception area at the top of the Herodium.
The modern staircase is where the final staircase was located. Note the series of arches in the top of the image. These supported the covering of this portion of the staircase. Note also the decorative cornices at the bases of the arches.
This staircase led up to the top of the "mountain" and was the formal entry into the upper palace. It was evidently built in two phases: arches below the current staircase are from the first phase of the staircase. It seems that the second (final) phase was constructed in anticipation of the visit of Marcus Agrippa, Augustus's right-hand man, in 15 or 14 BC.
After that visit, Herod began constructing his mausoleum to the east of this staircase. The staircase itself was covered over when the whole "mountain" was covered with fill that gave the "mountain" its distinctive volcanic shape—as a memorial mound. Thus, the staircase and the entrance at the top of it are very well preserved.
Josephus wrote in his Antiquities that ". . . it has a steep ascent formed of two hundred steps of hewn stone" and in War ". . . and provided an easy ascent by two hundred steps of the purest white marble."