After Alexander the Great's death in 323 BCE, Ptolemy I Soter, a Macedonian general, believed that Alexander's empire could not stay united. During the council at Babylon, he suggested dividing the empire's provinces among the generals and became satrap of Egypt, including adjacent Libyan and Arabian regions.

Ptolemy took advantage of Egypt's geographic isolation to build a great Hellenistic power. After successfully resisting Antigonus's attack on Egypt, Ptolemy, like the other satraps, assumed the title of king in 305–304 BCE. On November 7, 305 BCE, Ptolemy openly proclaimed himself king of Egypt and founded the Ptolemaic dynasty.

As ruler of Egypt, Ptolemy I Soter brought significant changes, including increasing cultivated land and introducing new crops, most notably Triticum durum wheat. He also introduced coinage to regulate financial affairs.

Ptolemy established the Serapis cult in Memphis, merging Egyptian and Greek religions, restored temples, and supported the Egyptian nobility and priesthood to win over the Egyptians. Additionally, he founded the Museum (Mouseion) as a workplace for scholars and artists and established the famous Library of Alexandria. He also founded the town of Ptolemais in Upper Egypt.

Ptolemy I Soter's rule significantly shaped Egypt's history and culture after his death. As the founder of the Ptolemaic dynasty, he established a Hellenistic kingdom that became the wealthiest and most powerful in the region.

Ptolemy I introduced coinage, which was new to Egypt at the time, and established the Serapis cult in Memphis, blending Egyptian and Greek religions. He also restored temples and founded the Library of Alexandria and the Museum, fostering arts and sciences. His dynasty saw efficient harnessing of resources, increased cultivation, and new crops, leading to a population boom.