Why are the exact dates of the Buddha’s life uncertain?

The uncertainty surrounding the exact dates of the Buddha’s life stems primarily from the significant gap between his death and the time his life story was first committed to writing.12

The earliest Buddhist texts were not recorded until shortly before the beginning of the Common Era, several centuries after he lived. Because of this delay, traditional accounts are often viewed by scholars as legendary rather than strictly historical, making it difficult to establish a precise chronology.123

Traditional sources offer a wide range of dates for his "passage into nirvana," spanning from 2420 BCE to 290 BCE. While 20th-century scholarship narrowed this focus, academic opinion remains divided between two primary theories:12
* Those who place his death at approximately 480 BCE.12
* Those who argue for a date about a century later.12

Ultimately, because the biographical tradition developed through the synthesis of independent fragments over many centuries, scholars have largely shifted their focus from seeking exact historical dates to studying the development and motivations behind these narratives.3