What happened following the death of the Buddha?

What happen is the Buddhist missionaries spread the new faith, first to Sri Lanka.

The Buddha had instructed his followers to cremate his body as the body of a universal monarch would be cremated and then to distribute the relics among various groups of his lay followers.

His body lay in a coffin for seven days before being placed on a funeral pyre and was set ablaze by the Buddha's chief disciple, who had been absent at the time of the Buddha's death.

After the Buddha's cremation, his relics were entrusted to a group of lay disciples, but armed men arrived from seven other regions and demanded the relics. In order to avert bloodshed, a monk divided the relics into eight portions.

Reference: Encyclopædia Britannica. "The Buddha's Relics." Encyclopædia Britannica, Encyclopædia Britannica, Inc.,