Daniel 11:6-10
Daniel 11:6
And in the end of years they shall join themselves together; for the king's daughter of the south shall come to the king of the north to make an agreement: but she shall not retain the power of the arm; neither shall he stand, nor his arm: but she shall be given up, and they that brought her, and he that begat her, and he that strengthened her in these times.
Syria had been considered the principal part of the Seleucid Kingdom.  In 285 B.C. Ptolemy I had died and Ptolemy II Philadelphus had taken over the rule.  He ruled from 285-245 B.C. He had raised an army of 200,000 infantrymen, 20,000 cavalry, 2,000 chariots and 400 Ethiopian elephants.  He had fought against Syria but then he finally made an alliance with Antiochus II Theos (the king of the north).  The king’s daughter was Berenice who married Antiochus making it part of the agreement.  To make room for Berenice, Antiochus banished his first wife Laodiceia.  Antiochus had promised Berenice that if she bore him a male child, he would make him his heir.  Now the story continues that after two years Antiochus brought back Laodiceia.  She then got revenge for being cast out the first time.  She poisoned Antiochus and Berenice and her son.  Shortly after that scenario, Ptolemy II Philadelphus died.
Daniel 11:7
But out of a branch of her roots shall one stand up in his estate, which shall come with an army, and shall enter into the fortress of the king of the north, and shall deal against them, and shall prevail:
“The branch of her roots” from the family line who took the place of Berenice was her brother Ptolemy III Eurgetes (246-221 B.C.)  He had raised up an army to fight against Seleucia and Antioch, Syria.  He took the fortress which was probably the one at Antioch and caused the present king of the north, Seleucus II Callinicus (246-223 B.C) to retreat beyond the Taunus mountains which was all the way up in the Roman Limes District of Germany.  Ptolemy III then ruled over Syria, Mesopotamia, some territories beyond the Tigris River.
Daniel 11:8
And shall also carry captives into Egypt their gods, with their princes, and with their precious vessels of silver and of gold; and he shall continue more years than the king of the north.
There was now occurring in Egypt rebellion so Ptolemy III had gone back to Egypt but this allowed Seleucus II Callinicus to regain the rule in Syria.  Ptolemy had taken 40,000 talents of silver and 2500 idols.  The Greek talent weighed 82 ¼ pounds so it might have been according to Greek weight.  The weight would have been 3,290,000 pounds of silver and by today’s value (3/14/17) would have a value of $271,227,600.  However, what the people loved about Ptolemy was that he brought back all the idols which were stolen by King Cambyses in 525 B.C. and placed them in the appropriate temples.  Since the Egyptians were heavily into idolatry, they named him “Euergetes” which in Egyptian means “Well-doer.”  Ptolemy III had ruled for 25 years and outlived Seleucus, King of Syria, by four years.
Daniel 11:9
So the king of the south shall come into his kingdom, and shall return into his own land.
Here we have a reiteration of verse 8 that Ptolemy III left Syria and came back to his kingdom of the south, that is, Egypt along with the idols and the 40,000 talents of silver. 
Daniel 11:10
But his sons shall be stirred up, and shall assemble a multitude of great forces: and one shall certainly come, and overflow, and pass through: then shall he return, and be stirred up, even to his fortress.
The son in view here was a son of Seleucus II whose name was Seleucus III Ceraunus (226-223 B.C.).  He had reigned for a period of three years.  He was fighting in Asia Minor when he was killed in action.  After the death of Seleucus III the army had placed Antiochus III the Great on the throne and he reigned for a period of 37 years (223-187 B.C.).  To overflow is a picture of force and fury.  In 221 B.C he had crushed a rebellion in the west and after that he began three campaigns against Egypt.  He amassed an army of 72,000 soldiers, 6000 horses and 102 elephants.  He took the fortresses that Egypt established in Seleucia, Tyre, Ptolemais and north Syria.  While he was attacking Dora which was on the Mediterranean coast of Syria, he had accepted a four month winter truce and then returned to his fortress at Ptolemais (or Seleucia.)