Daring Macedonian general who aided Alexander's conquest of Persia & northern India & eventually united most of Alexander's Asian empire [except for Palestine] under his own rule. Just Alexander's junior, Seleucus earned the respect of the conqueror & older officers for his performance in the Indian campaigns. So, when Perdiccas was named regent after Alexander's death (323 BCE), he made the energetic young general his viceroy [chiliarchos]. Yet when Perdiccas' troops mutinied during his invasion of Egypt, Seleucus restored order by joining other aides [Peithon & Antigenes] in assassinating their commander (321 BCE). When the regional governors redivided the Macedonian empire, Seleucus replaced Perdiccas as satrap [governor] of Babylonia.

Yet he was unable to secure his realm against the expansionist plans of Antigonus. In 316 BCE Seleucus abandoned Babylon & sought refuge with Ptolemy, leaving Antigonus free to annex almost all of Asia (316 BCE). But in the next coalition war he took his revenge. Though reduced to the rank of naval commander in Ptolemy's service, Seleucus plundered Antigonus' coastline, reclaimed Cyprus & joined forces with his host in defeating Antigonus' son, Demetrius, at Gaza (312 BCE). Then, turning East with a small contingent, he reclaimed Babylon without a fight & defeated the remaining Antigonid allies in Asia. After the truce of 311 BCE Seleucus was left as master of most Asian provinces with the notable exception of Phoenicia & Palestine, which Ptolemy had annexed in his ally's absence.

But the former exile was not content with a triumphant return.  In 305 BCE he, like other Hellenistic rulers, took the title of basileus ["king"] to counter Antigonus' royal pretensions. Then he came to the aid of Lysimachus in defeating Antigonus at the battle of Ipsus (301 BCE).  In the division of spoils, Seleucus claimed all of Syria & the eastern provinces of Asia Minor.  To solidify the control of his prize Mediterranean territories, he transferred his capital from Seleucia on the Tigris to the new city of Antioch [named for his father] on the Orontes in northwestern Syria (293 BCE), leaving his son, Antiochus, to rule the eastern provinces.

For almost two decades Seleucus was able to concentrate on consolidating his hold on his vast kingdom, bothered only by the few forces still loyal to the Antigonid cause now led by Demetrius. But in 282 BCE he was unexpectedly drawn into the family feud of his neighbor & former ally, Lysimachus, whose wife, Arsinoë, had convinced him to execute his oldest son by a former marriage on trumped up charges of treason. When the dead man's wife [Lysandra] & children sought refuge in Seleucus' court, he championed their cause by invading Lysimachus' domain. When the two septuagenarians met at Corupedium [in western Asia Minor] -- in rumored hand-to-hand combat -- Lysimachus was killed (281 BCE), leaving Seleucus the last survivor of Alexander's generals & the ruler of his whole Asian empire from the Bosporus to the Hindu Kush.

But with Lysimachus, the ruler of Thrace & Macedonia, gone another prize loomed on the horizon. Seleucus now had a chance to achieve a goal that had eluded all of his former comrades in arms: the reunification of all of Alexander's empire. So, instead of pausing to consolidate his conquest of Asia Minor, the old warrior launched an invasion of Europe. But before he could reach his homeland, he was killed -- not by opposing forces but by a guest in his own camp: Ptolemy's son Ceranus, who had been exiled by his brother, Ptolemy II Philadelphus. No motive was ever discovered for this assassination. But there is historical irony & poetic justice in the fact that Seleucus' rise to power, which was launched  by his unanticipated assassination of Perdiccas ended in his own unanticipated assassination. His ashes were enshrined by his son Antiochus I at Seleucia, where he was worshipped posthumously as Zeus Nicator, an incarnation of the head of the Greek pantheon.

References: Josephus, Antiquities 12.2,119,125,246,363; 13:213,267.
                   _____, Against Apion 2.39.
                   Appian, Roman History 11.55-63.
                   Justin, Epitome 15.4; 17.1-2. 
                   Pausanias, Description of Greece 1.6.4, 10.2-5.

Other resources on line:

• Seleucus I Nicator - illustrated essay in Wikipedia's web.

• The Syrian Wars - Chapters of Book 11 of Appian's Roman History that cover Seleucus' career [Livius: Articles in Ancient History].

• End of Seleucus Chronicle - deciphered fragments of cuneiform tablets tracing Seleucus' last years [Livius: Articles in Ancient History].

Currency issued by Seleucus perpetuated the iconography of Alexander's coins, with a profile of Herakles wearing a lion skin on the face & the image of an enthroned Zeus with scepter & eagle on the reverse. Seleucus simply had the features of Herakles altered to resemble his own & the inscription to the right of the throne changed from Alexandrou ["of Alexander"] to Selekou ["of Seleucus"]. Some---but not all---later coins, like the tetradrachma above, added the word Basileos ["king"] under the throne.