Please note that some of the details given below might be wrong, but if anyone knows something that sounds even vaguely familiar, please do not hesitate to post it.

So my friend and I were having a discussion, when he brought up a famous person (possibly a philosopher) who thought he had figured out the secrets to what happens after death, and to test it, instructed his disciple to kill him. He cannot remember the name of this person. I have Googled numerous phrases like "philosopher asks disciple to kill him", but I couldn't find anything remotely similar.

Any ideas who this person might be?