Armies were Led by Kings in Person
Source: TTT
2 Kings 18:13
In the fourteenth year of Hezekiah’s reign, Sennacherib king of Assyria attacked and captured all the fortified cities of Judah.
2 Kings 25:1
So in the ninth year of Zedekiah’s reign, on the tenth day of the tenth month, Nebuchadnezzar king of Babylon marched against Jerusalem with his entire army. They encamped outside the city and built a siege wall all around it.