Why did Siddharta Gautama leave his life of privilege to wander for years

Siddhartha was shielded from religious teachings or knowledge of human suffering by his father King Suddhodana. Yet, Siddhartha felt that material wealth was not the ultimate goal of life. At the age of 29, Siddhartha left his palace in order to meet his subjects. Despite his father's effort to remove the sick, aged and suffering from the public view, Siddhartha was said to have seen an old man. The prince went on further trips where he encountered, variously, a diseased man, a decaying corpse, and an ascetic. Deeply depressed by these sights, he sought to overcome old age, illness, and death by living the life of an ascetic.

Siddhartha escaped his palace leaving behind this royal life to become a mendicant. This event is traditionally called "The Great Departure".