Which were the four events in the life of the Buddha which have been depicted in different forms of Buddhist art? What did these events symbolise?

The main events associated with the Buddha’s life which were frequently depicted were events related to the birth, renunciation, enlightenment, dhammachakrapravartana, and mahaparinibbana (death). These four events were earlier depicted in symbolic form but with the advent of Gandhara school, the depiction got human form.
The four events can be symbolized accordingly-

• Birth- it generally depicts the birth of Gautam Buddha.
• Renunciation- it depicts the departure of Buddha from all worldly pleasures.
• Enlightenment- it is the attainment of enlightenment near Bodhgaya. It has mostly been represented by a peepal tree.
• Dhammachakrapravartana- it is the depiction of first sermon of Buddha at Sarnath.
• Mahaparinibbana (death)-this has been well represented at the Ajanta caves.