multiple solar deities and their mythologies that were passed down from one group to another. R. F. Littledale criticized the Sun myth theory, pointing out that by his own principles, Max Müller was himself only a solar myth. Alfred Lyall delivered another attack on the same theory's assumption that tribal gods and heroes, such as those of Homer, were only reflections of the Sun myth by proving that the gods of certain Rajput clans were actual warriors who founded the clans a few centuries ago, and were the ancestors of the present chieftains. Solar vessels and Sun chariots The Sun was sometimes envisioned as traveling through the sky in a boat. A prominent example is the solar barque used by Ra in ancient Egyptian mythology. The Neolithic concept of a "solar barge" (also "solar bark", "solar barque", "solar boat" and "sun boat", a mythological representation of the Sun riding in a boat) is found in the later myths of ancient Egypt, with Ra and Horus. Several Egyptian kings were buried with ships that may have been intended to symbolize the solar barque, including the Khufu ship that was buried at the foot of the Great Pyramid of Giza. Examples of solar vessels include: Neolithic petroglyphs which are interpreted as depicting solar barges. The many early Egyptian goddesses that were seen as sun deities, and the later gods Ra and Horus were depicted as riding in a solar barge. In Egyptian myths of the afterlife, Ra rides in an underground channel from west to east every night so that he can rise in the east the next morning. The Nebra sky disk, c. 1800-1600 BC, associated with the Unetice culture, which is thought to show a depiction of a solar barge. Gold lunulae associated with the Bell Beaker culture, c. 2400–2000 BC, thought to represent solar boats. Nordic Bronze Age petroglyphs, including those found in Tanumshede, often contain barges and sun crosses in different constellations. Solar boat imagery also appears on bronze razors from the period. Minature gold boats from Nors in Denmark, dating from the Nordic Bronze Age. The Caergwrle Bowl from Wales, dating from the British Bronze Age, c. 1300 BC. Solar boat motifs depicted on bronze artefacts from the Urnfield culture and Lusatian culture, c. 1300-500 BC. Depictions of solar boats on Iron Age Celtic artefacts, such as the Petrie Crown from Ireland (1st century AD), and ornaments