The sons of Seleucus II were:
Seleucus III Ceraunus, who ruled from 226 to 223 BC, and
Antiochus III the Great, who ruled from 223 to 187 BC.
a great army … sweeping through like a flood: Antiochus III aggressively tried to reclaim lost lands, including Palestine.
as far as his fortress: Antiochus III advanced to Raphia, near Egypt's border, in 217 BC. In the battle that followed, the king of the south, Ptolemy IV Philopater, who ruled from 221 to 203 BC, defeated Antiochus III and kept control of Palestine.