Daniel 11:13 (ESV)

13 For the king of the north shall again raise a multitude, greater than the first. And after some years he shall come on with a great army and abundant supplies.

The king of the north, Antiochus III, is given peace and the opportunity to recover from his defeat. He creates an army that is even larger than the previous time. After several years of gathering the army, he marches with that mighty army to the south. We must remember that we are dealing with prophecy here. The Lord is showing what is about to happen! He reigns. From history we know that this is twelve years later. Then Antiochus III marches up against the king of Egypt. At this time, Ptolemy IV is no longer king. His four-year-old son, Ptolemy V, is now nominally king. The king of the north quickly moves his army to the south in order to overwhelm Egypt with a surprise attack.