Solar barques were the vessels used by the sun god Ra in ancient Egyptian mythology. During the day, Ra was said to use a vessel called the Mandjet (Ancient Egyptian: mꜥnḏt) or the Boat of Millions of Years (Ancient Egyptian: wjꜣ-n-ḥḥw), and the vessel he used during the night was known as the Mesektet (Ancient Egyptian: msktt).
Ra was said to travel through the sky on the barge, providing light to the world. Each twelfth of his journey formed one of the twelve Egyptian hours of the day, each overseen by a protective deity. Ra then rode the barque through the underworld, with each hour of the night considered a gate overseen by twelve more protective deities. Passing through all of these while fending off various destructive monsters, Ra reappeared each day on the eastern horizon. He was said to travel across the sky in the Mandjet Barque through the hours of the day, and then switch to the Mesektet Barque to descend into the underworld for the hours of the night.
The progress of Ra upon the Mandjet was sometimes conceived as his daily growth, decline, death, and resurrection and it appears in the symbology of Egyptian mortuary texts.
In folklore, a boat of this kind is used by the sun god. Thus, as the pharaoh was a representation of the sun god on earth, the king would use a similar boat upon his death to travel through the underworld on their journey to the afterlife.
One of the most well known examples of this is the Khufu ship, which was built and then buried at Giza along with Khufu and the rest of the items he would take with him to the afterlife. The ship was originally displayed in the specially-built Giza Solar boat museum, but was subsequently moved to the Grand Egyptian Museum.
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