Daniel 11:20

‘Then will stand up in his place one who will cause an exactor to pass through the glory of the kingdom, but within few days he will be destroyed, neither in anger nor in battle.'

This was Antiochus III's elder son, Seleucus IV, who succeeded his father. He taxed his people, including Israel, so heavily to pay the Roman indemnity that he was poisoned, by his prime minister, Heliodorus. Heliodorus was probably the exactor that Seleucus sent through "the jewel (glory) of his kingdom," that is, Israel, collecting taxes, and with the special intention of robbing the temple treasury (2MMalachi 3:7). So Seleucus IV did not die through mob violence, as his father did, nor did he die in battle. Rather he died from poison.

‘Within few days', that is, within a comparatively short time of his blasphemous activity.