Ptolemy II Philadelphus: History, Reign & Achievements

In 282 BC, King Ptolemy II Philadelphus became the second ruler of the Ptolemaic Dynasty of Egypt, a Macedonian dynasty that ruled Egypt for almost three centuries, from 305 BC to 30 BC. He ranks up there as one of the empire’s most successful rulers. Through his excellent diplomacy skills, he was able to successfully expand the empire.

The Egyptian ruler’s reign spanned from 284 BC to 246 BC, making him the second ruler of his dynasty. He was an ardent supporter of education. He ensured that funds were made available for the completion of many infrastructural projects that were started by his father and predecessor, Ptolemy I Soter. One of such monumental projects was the Great Library of Alexandria, a library that housed up to half a million papyrus scrolls. Ptolemy II’s reign successfully transformed the city of Alexandria into the leading destination for trade, arts, and sciences.

What else was Ptolemy II Philadelphus known for? And how did he come to be called Philadelphus?

Below, World History Edu takes a detailed look at the life, reign and major accomplishments of this Egyptian ruler of Greek origins.

Ptolemy II Philadelphus – second king of the Ptolemaic Dynasty of Egypt

The Early Life of Ptolemy II

Ptolemy II was born on the Greek island of Kos. His parents were Ptolemy I Soter and Berenice I. His father, Ptolemy I, was the famous Macedonian nobleman and general who founded the Ptolemaic Dynasty of Egypt.

He had many siblings, including his full-blooded sisters, Arsinoe II and Philotera. Growing up, Ptolemy received the best education, as his father believed that it would prepare him to be a good and wise ruler.

Before his birth, his half-brother, Ptolemy Keraunos had been in line to succeed their father. However, as Ptolemy grew older, the two brothers fought over who would take over after their father’s passing. Ptolemy eventually won and Keraunos left Egypt.

In 284 BC, Ptolemy I declared his young son as king. Because the older king was alive, Ptolemy received the title of co-regent and he served in that capacity until 282 BC, when his father died. Many historians speculate that Ptolemy killed his father whereas others believe the king died of old age.


Ptolemy’s reign was nothing short of controversial, as it was filled with family rivalries, conflicts, expansions, and major wars.

Family Tensions

Despite having taken over after his father’s death, Ptolemy’s rivalry with his brother Keraunos continued. Their conflict might have likely been the reason why the new king ordered the execution of two of his other half-brothers, who might have been Keraunos’ full brothers.

After Keraunos left Egypt, he sought support from the King of Thrace, Lysimachus. However, this alliance caused divisions in the king’s court, especially since Lysimachus was Ptoleymy’s brother-in-law through his marriage to Arsinoe II.

On the other hand, Lysimachus’ successor, Agathocles, was also married to Keraunos’ sister Lysandra. Eventually Lysimachus decided to support Ptolemy and strengthened their relationship by giving his daughter Arsinoe I’s hand in marriage to the newly-installed ruler of Egypt.

Meaning of Philadelphus

However, relationships soured over time after Lysimachus’ empire crumbled. His wife, Arsinoe II, returned home to Egypt and fell out with Arsinoe I. Around 275 BC, Ptolemy banished his wife Arsinoe after she was charged with conspiracy. He later married his sister, and due to their incestuous union, the two were given the name “Philadelphoi”, which meant “sibling lovers.”

Wars & Expansions

During the days of Ptolemy I, the older king maintained strong diplomatic relations with his friend, Seleucus I, who ruled over Mesopotamia. But their relationship grew weaker following the Battle of Ipsos in 301 BC, when they both claimed the land of Syria. Nonetheless, their claims never led to a war.

Under Ptolemy II, that all changed. As Seleucus’ son, Antiochus I, tried to regain much of his father’s empire, the king used it as an opportunity to expand the Ptolemaic Kingdom. This led to a fierce battle between the two successors, with Ptolemy emerging victorious.

Around 275 BC, Ptolemy was ready to further expand his territory and invaded the Kingdom of Nubia. He was able to successfully annex twelve miles of land, including the gold mines at Wadi Allaqi. His next mission was to colonize the Red Sea. He established several port towns along the Red Sea coast, which served as important trading routes in the region.

Between 267-261 BC, Ptolemy fought in the Chremonidean War that occurred between Macedonia and Greece. At that time, Egypt had one of the strongest navies in the Mediterranean, and Ptolemy forged alliances with Athens and Sparta, mostly providing naval power and funding in order to protect Greece from Macedonia.

The Second Syrian War occurred between 260-253 BC between Ptolemy and Antiochus II. The confrontation was over who would conquer the cities located in Asia Minor.

Eventually, both parties met to negotiate the terms of a treaty, which resulted in Ptolemy giving up most of Asia Minor’s territories to Antiochus II. The peace was further solidified when Ptolemy offered Antiochus his daughter’s hand in marriage.


Following the Second Syrian War, Ptolemy remained active in diplomatic affairs, and in 249 BC, he founded a festival called Ptolemaia. He died in January 246 BC and was succeeded by his eldest son, Ptolemy III.

Ptolemy II was succeeded to the throne by his eldest son Ptolemy III in 246


Ptolemy II Philadelphus was regarded as a successful ruler even though he wasn’t necessarily a man of peace. During his reign, he developed agriculture and opened up trading routs that led to more commercial activities. Because the peasants that dwelled in the Nile Valley provided labor at relatively cheaper cost, Egypt did not have to rely on slavery as a strategy to boost the kingdom.

He also built on the amazing works of his father, which in the end contributed to the development of the city of Alexandria. Ptolemy’s well-thought out policies further enhanced the image of Alexandria, making it one of the main trading centers along the Mediterranean.

Ptolemy was also avidly interested in religion, and under his reign, he built many temples, including ones in honor of Serapis, the Greco-Roman god of healing. Like the ancient Egyptian rulers that came before him, Ptolemy was quick to deify himself and his family, including his parents and sister. This practice eventually became very popular, especially among the Romans.

He also completed projects that his father, Ptolemy I, had begun during his reign, including the famous Lighthouse of Alexandria. The lighthouse a groundbreaking architectural and engineering marvel of the highest order. Estimated at around 400 feet, the Lighthouse of Alexandria was completed by Ptolemy to aid sailors as they approached the somewhat treacherous coastline of the city.

He also strongly advocated for the arts and science. This Ptolemaic king’s had very big ambitions for city, including pursuing the goal of making the rest of the world to recognize Alexandria as a hub for higher learning.

Ptolemy II expanded the Library of Alexandria and financially supported many poets and academics. Many people traveled to Alexandria to study mathematics, natural science, philosophy, and literature.

Like many other rulers before and after him, Ptolemy II Philadelphus had his shortcomings, but he made up for those through strategic diplomacy and desire to support Alexandria’s educational and business sectors.

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