WHO WAS PTOLEMY I SOTER.

Ptolemy I Soter (305-283/2 BC) served with Alexander from his first campaigns, and played a principal part in the later campaigns in Afghanistan and India.
Ptolemy I participated in the Battle of Issus (Nov. 33BC), the 2nd great battle of Alexander's conquest of Asia, that occurred in Southern Anatolia, between the Hellenic League led by Alexander the Great and the Achaemenid Empire, led by Darius III.
During Alexander's campaign to conquer the Persian Empire, Ptolemy was the one who accompanied him during his journey to the Oracle in the Siwa Oasis, in Egypt, supposedly by following birds across the desert. The Oracle confirmed him as both a divine personage and the legitimate Pharaoh of Egypt and he was proclaimed a son of Zeus.
The earliest evidence of the place in connection with ancient Egypt is in the 26th Dynasty, when a large cemetery with elaborated tomb monuments was established (necropolis) there. During Ptolemaic period its ancient Egyptian name was "Field of Trees." Greek settlers of Cyrene, the oldest and most important of the 5 Greek cities in the region and later a Roman city, made the connection with the Oracle as mediums around 7th BC and the Oracle temple of Zeus (Amun, Ammon) took the image of a "ram." According to the historian Herodotus, the "Fountain of the Sun" was placed there which ran coldest in the noontide heat. Iarbas, a mythological king of Libya, was also considered a son of Ammon.
The Siwa Oasis, is a deep depression that reaches below sea level, to about -19m. To the West the Jaghbub Oasis lies in a similar depression and to the East the large Katara Depression. Siwa is between the Katara Depression and the Egyptian Sand Sea in the Western Desert, near East of the Libyan border and 560km/348mi from Cairo. The Oasis is about 80km/50mi in length and 20km/12mi wide, and it is one of the most isolated settlements, with 23,000 people, mostly Berbers who developed a unique culture and a distinct language called Siwi. It is a branch of an Afro-Asiatic language of North Africa, and now spoken by large populations in Algeria and Morocco, and by smaller populations in Libya, Tunisia, Northern Mali, Wester and Northern Niger, Northern Burkina Faso, and Mauritania. The region is believed to have been inhabited by Berbers from at least 10,000 BC. Its fame lies primarily in its ancient role as the home to the Oracle. The solitary Oracle was a place considered to provide to its representatives or mediums, by using a form of divination, a wise and insightful counsel or prophetic predictions or precognition of the future.
Ptolemy had his first independent command during the campaign against the rebel Bessus, also known as Arta'Xerxes V, a prominent Persian Strap of Bactria in Persia, and later self-proclaimed King of Kings of Persia. He killed his predecesor and relative, Darius III, after the Persian army had been defeated by Alexander the Great. After hours of intense  and fierce fighting, Arta'Xerxes survived the battle and remained with Darius, his king, whose routed army eluded Alexander's forces and spent  the Winter in Ecbatana literally meaning "the place of gathering, an ancient city in Media, best known for having been the political and cultural base of the Medes. The next year Darius attempted to flee to Bactria in the East. Arta'Xerxes, conspiring with fellow satraps, deposed Darius and put him in golden chains.  He may have intended to surrender the deposed king to the Macedonians and obtain a political gain through it, but Alexander ordered his forces to continue to pursue the Persians. The panicked conspirators stabbed Darius and left him dying in a cart yo be found by a Macedonian soldier. Arta'Xerxes immediately proclaimed himself King of Kings of Persia, but since most of the Persian Empire had already been conquered, he was not regarded as that. Ptolemy captured Arta'Xerxes and handed him over to Alexander for execution. He was executed in 329 BC.
During Alexander's campaign in the Indian subcontinent Ptolemy was in command of the advance guard at the siege of Aornos (meaning 'fortified place'), the ancient Greek name for the site of Alexander's last siege at a mountain site located in modern Pakistan. The rocky mountain had a flat summit well supplied with natural springs and wide enough to grow crops. Neighboring tribesmen who surrender to Alexander offered to lead him to the best point of access. Then the Battle of Hydaspes was fought by Alexander in 326 BC against King Porus of the Paurava kingdom on the banks of the River Hydaspes (now Jhelum) in the Punjab near Bhera. Alexander decision to cross the monsoon-swollen River despite close Indian surveillance, in order to catch Porus' army in the flank. Monsoon is defined as a seasonal reversed wind accompanied by changes in precipitation with the heating of land and sea.
The Battle historically opened up India to Greek political and cultural influences which continued to have a profound impact in the following centuries.
When Alexander died in 323 BC, Ptolemy is said to have instigated the resettlement of the empire made at Babylon. Through the Partition of Babylon, he was appointed satrap of Egypt.  In 321BC, Perdicass, the imperial regent, attempted to invade Egypt only to fall at the hands of his own men. He was murdered in his tent by two of his subordinates. Ptolemy was consistent in his policy of securing a power base, while never succumbing to the temptation of risking all to succeed Alexander. His first goal was to hold Egypt securely, and his second was to secure control in the outlying areas: Cyrenaica and Cyprus, as well as Syria, including the province of Judea. Ptolemy seems to have mingled as little as possible in the rivalries between Asia Minor and Greece; he lost what he held in Greece, but re-conquered Cyprus in 295/294. Cyrene, after a series of rebellions, was finally subjugated about 300 BC and placed under his stepson Magas.
In 289, Ptolemy made his son by Berenice -Ptolemy II Philadelphus- his co-regent. His eldest legitimate son, Ptolemy Keraunos, whose mother Eurydice, daughter of Antipater, had been repudiated, fled to the court of Lysimachus. Ptolemy also has a consort, Thais, a famous Greek hetaera (a member of a class of highly cultured courtesans), famous for instigating the burning of Persepolis, the ceremonial capital of the Achaemenid empire, as a retribution for Arta'Xerxes' burning of the old Temple of Athena on the Acropolis in Athens (the site on the extant Parthenon).  She is said to have been very witty and entertaining. She bored Ptolemy three children. She also was one of Alexander's companions in his conquest of the ancient World.
Ptolemy I Soter died in winter 283 BC at the age of 84. Shrewd and cautious, he had a compact and well-ordered realm to show at the end of 40 years of war. His reputation attached the floating soldier- class of Macedonians and other Greeks to his service. He was a ready patron of letters, founding the Great Library of Alexandria.