Commentators unanimously identify the "mourning of Hadadrimmon in the valley of Megiddon" as the national lament over the death of the righteous King Josiah. This event, recorded in 2 Chronicles 35, was so devastating for Israel that it became the ultimate benchmark for grief, even becoming an annual ordinance. Zechariah uses this powerful historical memory to illustrate the profound depth of the future mourning he prophesies.