In this picture provided by Greece's Culture ministry on Sunday, Oct. 12, 2014, a partly damaged floor mosaic is shown inside an ancient Greek tomb, depicting a chariot driver, two horses and the Greek god Hermes. Archaeologists digging through an ancient grave at Amphipolis, northern Greece, uncovered the 3-by-4.5 meter (10-by-15 ft.) mosaic in what is likely the antechamber to the main burial room. (AP Photo/Greek Culture Ministry)

Archaeologists digging through a vast ancient tomb in Amphipolis in northern Greece have uncovered a floor mosaic that covers the whole area of a room seen as the antechamber to the main burial ground.

The mosaic, 3 meters (10 feet) long and 4.5 meters (15 feet) wide, depicts a horseman with a laurel wreath driving a chariot drawn by two horses and preceded by the god Hermes. According to a Culture Ministry announcement on Sunday, Hermes is depicted here as the conductor of souls to the afterlife.

The mosaic is made up of pebbles in many colors: white, black, gray, blue, red and yellow. A circular part, near the center of the mosaic, is missing, but authorities say enough fragments have been found to reconstruct a large part.

The ministry says that archaeologists have dated the mosaic to the last quarter of 4th century B.C. (325-300 B.C.), consistent with their belief the grave contains the remains of a contemporary of Alexander the Great, the ancient Greek King of Macedonia, who conquered the Persian Empire and reached present-day India, Afghanistan and Uzbekistan in a whirlwind campaign, from 334 to 323 B.C. The grave may be that of a relative or general of Alexander's, archaeologists have speculated.

Alexander himself, who died in Babylon in present-day Iraq at age 32, in 323 B.C., is believed to have been buried in Egypt. But his tomb hasn't been found.

In this picture provided by Greece's Culture ministry on Sunday, Oct. 12, 2014, the ancient Greek god Hermes is depicted in a mosaic as the conductor of souls to the afterlife. Archaeologists digging through an ancient grave at Amphipolis, northern Greece, uncovered the 3-by-4.5 meter (10-by-15 ft.) mosaic in what is likely the antechamber to the main burial room. (AP Photo/Greek Culture Ministry)

Explore further Greek archaeologists enter large underground tomb

© 2014 The Associated Press. All rights reserved.