Hastings' Dictionary of the Bible 
SELEUCUS . 1. Seleucus I , ( Nikator ), originally a cavalry officer of Alexander the Great, became satrap of Babylon on the death of the king. After some vicissitudes his position there was securely established in b.c. 312, from which date the Seleucid era was reckoned ( 1Ma 1:18 ). The battle of Ipsus, b.c. 301, made him master of Syria and great part of the East. He founded Antioch and its fortified port Seleucia ( 1Ma 11:8 ), and is said by Josephus ( Ant. XII. iii. 1) to have conferred on the Jews the privileges of citizenship. He is the ‘one of his [ i.e. the king of Egypt’s] princes’ ( Daniel 11:5 ). He died b.c. 280. 2. Seleucus ii . ( Callinicus , b.c. 246 226), son of Antiochus Soter , is entitled the ‘king of the north’ in the passage ( Daniel 11:7-9 ) which alludes to the utter discomfiture of the Syrian king and the capture of Seleucia. 3. Seleucus III . ( Ceraunus , b.c. 226 223), ‘one of his [Seleucus ii.’s] sons’ ( Daniel 11:10 ), was murdered during a campaign in Asia Minor: the struggle with Egypt was continued by his brother Antiochus ( Daniel 11:10-16 ). 4. Seleucus IV . ( Philopator ; but Jos. [Note: Josephus.] , Ant. XII. iv. 10, calls him Soter ), son of Antiochus The Great , reigned b.c. 187 176. He it was who despatched Heliodorus to plunder the Temple ( 2Ma 3:1-40 , cf. Daniel 11:20 ). 5. Seleucus V . (b.c. 125 124) and VI . (b.c. 95 93) are not of importance to the Biblical student. The four first-named belong to the ‘ten horns’ of Daniel 7:24 .
Cyclopedia of Biblical, Theological and Ecclesiastical Literature 
( Σέλευκος , a common Greek name), the name of several of the kings of the Greek dominion of Syria (q.v.), hence called that of the Seleucidae. (See Antiochus). Of these one only is named in Scripture, although several are referred to in Daniel 11.
International Standard Bible Encyclopedia 
sḗ - lū´kus ( Σέλευκος , Séleukos ):
(1) Seleucus I (Nicator, "The Conqueror"), the founder of the Seleucids or House of Seleucus, was an officer in the grand and thoroughly equipped army, which was perhaps the most important part of the inheritance that came to Alexander the Great from his father, Philip of Macedon. He took part in Alexander's Asiatic conquests, and on the division of these on Alexander's death he obtained the satrapy of Babylonia. By later conquests and under the name of king, which he assumed in the year 306, he became ruler of Syria and the greater part of Asia Minor. His rule extended from 312 to 280 BC, the year of his death; at least the Seleucid era which seems to be referred to in 1 Maccabees 1:16 is reckoned from Seleucus I, 312 Bc to 65 BC, when Pompey reduced the kingdom of Syria to a Roman province. He followed generally the policy of Alexander in spreading Greek civilization. He founded Antioch and its port Seleucia, and is said by Josephus ( Ant. , Xii , iii, 1) to have conferred civic privileges upon the Jews. The reference in Daniel 11:5 is usually understood to be to this ruler.
(2) Seleucus 2 (Callinicus, "The Gloriously Triumphant"), who reigned from 246 to 226 BC, was the son of Antiochus Soter and is "the king of the north" in Daniel 11:7-9 , who was expelled from his kingdom by Ptolemy Euergetes.
(3) Seleucus 3 (Ceraunus, "Thunderbolt"), son of Seleucus II, was assassinated in a campaign which he undertook into Asia Minor. He had a short reign of rather more than 2 years (226-223 BC) and is referred to in Daniel 11:10 .
(4) Seleucus 4 (Philopator, "Fond of his Father") was the son and successor of Antiochus the Great and reigned from 187 to 175 BC. He is called "King of Asia" ( 2 Maccabees 3:3 ), a title claimed by the Seleucids even after their serious losses in Asia Minor (see 1 Maccabees 8:6; 11:13; 12:39; 13:32 ). He was present at the decisive battle of Magnesia (190 BC). He was murdered by Heliodorus (which see), one of his own courtiers whom he had sent to plunder the Temple ( 2 Maccabees 3:1-40; Daniel 11:20 ).
For the connection of the above-named Seleucids with the "ten horns" of Daniel 7:24 , the commentators must be consulted.
Seleucus 5 (125-124 BC) and Seleucus 6 (95-93 BC) have no connection with the sacred narrative.