The Ascended Master Serapis Bey is the Lord (Chohan) of the Fourth Ray and Hierarch of the Ascension Temple at Luxor, Egypt. Some fourth-ray qualities are purity, discipline, joy, hope and excellence.

He is known as the great disciplinarian, he reviews and trains candidates for the ascension.

In the nineteenth century, Serapis Bey worked closely with El Morya, Kuthumi, Djwal Kul and other Masters to found the Theosophical Society.

Serapis was embodied as a high priest in the ascension temple on Atlantis more than 11,500 years ago.

He was the Egyptian pharaoh Amenhotep III, c. 1417-1379 BC called "the Magnificent." He brought Egypt to its height of diplomatic prestige, prosperity and peace. His extensive building of monuments, palaces and temples included construction of the temple of Luxor, which was built to correspond to the outline of the human skeletal framework. Careful studies of its architecture have revealed that the entire temple explains many secret functions of the organs and nerve centers.

Serapis was also embodied as Leonidas, king of Sparta. In about 480 b.c., with only three hundred soldiers, he resisted the advance of Xerxes' vast Persian army in a herculean effort at Thermopylae. Though finally defeated, their fight to the last man is celebrated in literature as the epitome of heroism in the face of overwhelming odds.

Serapis Bey supposedly ascended in about 400 BC.