The Origin of Zen

At the famous assembly on Vulture Peak, the Great Sage of the Shakya Clan sat down to give a sermon, but instead of speaking he merely blinked his eyes and held up a flower.

Of all those present, most were bewildered or had no reaction at all. Only Mahākāśyapa smiled. Upon which Shakyamuni said:

"I possess the true Dharma eye, the marvelous mind of Nirvana, the true form of the formless, the subtle dharma gate that does not rest on words or letters but is a special transmission outside of the scriptures. This I entrust to Mahākāśyapa."

Now. Did anything actually happen that day on Vulture Peak? And was anything actually said, or not?