There is a small story behind this dream. Adi Shankara is very renowned as the re-invigorator of the Advaita philosophy. One day I found the beautiful work of His, named vivekachudamani, and started working on its translation.
The same evening, I met another person who claimed that atheism and Nietszche philosophy are far more superior to the denial which Upanishat creates. She also claimed that she has gone through vivekachudamani and other texts without much satisfaction. I stopped talking on that issue due to ideological differences, but thought more about the criticism she made.
For a moment my faith was trembling. Then came the night and the inevitable sleep. I saw Adi Shankara in my dream. He chanted a few verses and then Lord Vishnu and Shiva appeared together in front of me. I forgot the chant by the morning, however.