The Feast of the Transfiguration has been celebrated in the East since the fourth century in remembrance of the occasion in the Gospel account when Jesus' appearance was gloriously transformed. That day on a mountaintop he stood in the company of two departed saints - Moses and Elias - whose appearance was also glorious. That day his Father in heaven appeared, gave witness to his Son, and commanded us to "hear him."
read on: http://orderofcenturions.org/documents/transfiguration.html
A great resource on the web with some very nice Icons is this essay:
THE SYMBOLISM OF THE SKÃNÃ ENTITLED: "The SkÃ©nÃ© Â A Universal Symbol of the Divine Presence: