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 m (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 the ministry of culture announcement made 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.