Final answer:
The earliest-known narratives of Jesus's life, the four Gospels, were written approximately sixty years after his execution, around 90 CE, and transmitted initially by oral tradition.
Step-by-step explanation:
The earliest-known narratives of Jesus's life, the four Gospels, were written by his followers and other early Christians. These accounts - Matthew, Mark, Luke, and John - provide the major source of information on Jesus's life and teachings. According to most scholars, the written gospels date to approximately 90 CE, which is about sixty years after Jesus's execution circa 30 CE. Initial transmission of the Gospels was orally before eventual documentation in their definitive versions. The Gospels, while differing in precise language and description of events, largely agree on the major aspects of the life of Jesus.
Christianity began with these narratives that originated from those closest to Jesus, known as disciples or apostles, and spread by figures such as St. Paul. The process of writing and standardizing these texts took place over decades, reflecting debates and discussions within the early Christian communities. These accounts exist in a broader historical and cultural context that influences our understanding of the figure of Jesus and the development of Christianity.