Flavius Josephus, Antiquities of the Jews
William Whiston, A.M., Ed.

[193] But then Salome and Alexas, before the king's death was made known, dismissed those that were shut up in the hippodrome, and told them that the king ordered them to go away to their own lands, and take care of their own affairs, which was esteemed by the nation a great benefit. And now the king's death was made public, when Salome and Alexas gathered the soldiery together in the amphitheater at Jericho; and the first thing they did was, they read Herod's letter, written to the soldiery, thanking them for their fidelity and good-will to him, and exhorting them to afford his son Archelaus, whom he had appointed for their king, like fidelity and good-will. After which Ptolemy, who had the king's seal intrusted to him, read the king's testament, which was to be of force no otherwise than as it should stand when Caesar had inspected it; so there was presently an acclamation made to Archelaus, as king; and the soldiers came by bands, and their commanders with them, and promised the same good-will to him, and readiness to serve him, which they had exhibited to Herod; and they prayed God to be assistant to him.