Alexander the Great built an empire during the latter part of the first millennium BC, including Egypt which he captured in about 332 BC. Though he ordered the building of a great city in his name on the Egyptian Mediterranean coast, he was not finished with his conquests and would soon depart the country, leaving behind a banker of Naucratis named Cleomenes as Egypt's satrap, or governor. He was greatly despised. Demosthenes called him "Ruler of Egypt and dishonest manipulator of the country's lucrative grain trade". Aristotle even spoke up, concurring and citing Cleomenes' numerous incidents of fraudulent conduct with merchants, priests of the temple and government officials. The Roman historian Arrian added his own assessment, telling us that "he was an evil man who committed many grievous wrongs in Egypt"

When Ptolemy I took over the post from Clemones in Egypt, he had little option but to try, sentence and execute Cleomenes. Ptolemy I is thought to have been the son of Lagus, a Macedonian nobleman of Eordaea. His mother's name was Arsinoe. He was a boyhood friend of Alexander the Great at Pella, and later became one of his most trusted generals as well as a member of his royal bodyguards. 

After Alexander's death in 323 BC, Ptolemy I, at least nominally continued to act as satrap for a time under Alexander's successors, but these were apparently not strong rulers and soon the empire created by Alexander began to break up. Hence, Alexander's generals, known as the diadochi (followers), divided up the conquered territories for themselves. We tend to think of Ptolemy I as then becoming the king of Egypt, but this was not entirely true. Nominally, he was answerable to the Council of State that had been set up in Babylon after Alexander's death, and to Perdiccas, the regent who held Alexander's signet ring. Matters at this point were far from settled as to the ultimate ruler of Egypt. 

There are various legends about the burial of Alexander, most of which culminate with his body being under the control of Ptolemy I. This gave Egypt's satrap both political and religious advantage, and Perdiccas realized this. In fact, so important was Ptolemy I's advantage that, in the spring of 321 BC, Perdiccas marched against him with an army of 5,000 cavalry and 20,000 infantry. However, he was repulsed by Ptolemy I near Memphis and then Perdiccas was murdered by his own officers. 

Nevertheless, the diadochi continued to war amongst themselves, although Antigonus Gonatus, Commander of the Grand Army, tried to keep them under control with a firm policy of repression, replacement and execution when necessary. To keep him at bay, three of the diadochi, consisting of Ptolemy I, Lysimachus and Cassander, entered into an uneasy partnership that would finally pay off. When Antigonus prepared to attack Cassander in Macedon, Ptolemy I marched against Antigonus' son, Demetrius Poliorcetes and defeated him at Gaza in 312 BC. After that, there was a peace treaty signed the following year confirming Ptolemy I as satrap in Egypt. 

However, wars between the diadochi persisted, and in 306 BC, Ptolemy I lost a sea battle at Salamis in Cyprus against Demetrius, though he held back Antigonus on land the same year at Gaza. It is said that he defended the Rhodians against Demetrius in 305 BC, and for this received from them his title Soter, meaning "Saviour". It was actually in November of that year that some ancient sources tell us that he officially assumed the kingship of Egypt. (Though this is not certain, he almost certainly assumed the kingship between 304 and 306 BC). Then, in 301 BC at the battle of Ipsus, Antigonus was killed, and the three allies were finally able to divide up the empire between themselves. Not only did Ptolemy become supreme ruler of Egypt, but also added Palestine and lower Syria to his empire. Under his rule, all of these territories appear to have prospered.  

Ptolemy I Soter took the Egyptian name Meryamun Setepenre, which means "Beloved of Amun, Chosen of Re". Hence, he attempted to take on the guise of a Pharaoh as other foreign rulers before him, and is even said to have married a daughter of Nectanebo II, though this is by no means certain. However, as early as 320 BC, he had her set aside for Eurydice, the daughter of Antipater, who was regent of Macedon. By her, Ptolemy I had four children and possibly more, and then another three by Berenice, a widowed lady-in-waiting to Eurydice. 

Even prior to his possible marriage to the daughter of Nectanebo II, Ptolemy is known to have married at least once, if not twice. Some sources provide that his first marriage was to a lady named Thais, who was an Athenian hetera, and it is fairly well known that he was married to a Persian princess named Artacama (Artakama), but there is never further mention of her after the wedding. 

By Thais, some sources report that he had three children named Lagus, Leontiscus and Eirene. By Eurydice, his children included Ptolemy Ceraunus, an unknown son, Ptolemais, Lysandra and possibly Meleager and Argaeus. His union with Berenice apparently was responsible for his heir to the Egyptian throne, Ptolemy II, as well as Arsinoe II and Philotera. 

Egypt's first ruler of the Ptolemaic Dynasty became a monarch in the Hellenistic whole while at the same time continued the line of god-kings in Egypt, wisely paying at least lip service to the prominent priesthood, who not only helped keep the population in check but also provided an excellent civil service that provided the country with stability and allowed it to prosper.

If Ptolemy I Soter did not complete the many great works he began, we can certainly admire his imagination and efforts. It was he who, in 290 BC, began the construction of the Pharos Lighthouse in Alexandria, though it was unfinished at his death in about 285 BC (some sources day 283 BC, at the age of 84) and had to be completed by his son and successor, Ptolemy II Philadelphus. It was he who erected the great Mouseion, Alexandria's famous ancient university though it would again be his son who would really establish it by inviting world renowned scholars to live in Egypt. However, it was also Ptolemy I who created the famous Library of Alexandria, and who obsessively filled it with the books that would allow his son to tempt away these scholars to Egypt. It should be noted that this king was also responsible for having the Hebrew Bible translated into the Greek language. Ptolemy I not only supported the intellectual foundations of Alexandria, he was also somewhat of a scholar himself, writing a history of Alexander the Great.

Demetrius Phalereus, the first head of the ancient Alexandria Library and one who was also instrumental in creating the Mouseion, advised Ptolemy I to "collect together books on kingship and the exercise of power, and to read them". It seems likely that Ptolemy I at least attempted to follow this advice, judging from his success in governing the territories under his authority. He sought to consolidate the religions of the Egyptians and Greeks by actually creating the worship of a new god named Serapis, which was in reality a composite deity made up of both Egyptian and Greek gods. Ptolemy I established for this god the Sarapeion in Alexandra, a temple dedicated to the god which also held a daughter library to that of the Great Library of Alexandria. He was also responsible for many other temples and temple additions in Egypt, which undoubtedly proved useful with his relationship to Egypt's powerful priesthood. 

This is not to say that Ptolemy I was entirely successful. Serapis, though becoming a popular god not only with the Greeks in Egypt but elsewhere in the world, seems to have never really attained that stature among the Egyptians themselves, who went about mostly worshipping their old gods. In addition, choosing Alexandria as his capital segregated the Greeks of his generation and their descendents from the Egyptian people. In fact, Alexandria came to be considered more of a Greek city in Egypt, rather than actually an Egyptian city. 

Ptolemy I Soter was probably buried in Alexandria in the royal necropolis, but alas, not much if any of that cemetery has ever been found. He was succeeded in death by his son who became known as Ptolemy II and who may have shared a co-regency with his father for a period of time before Ptolemy I's death. 

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