The Norse Vikings used a system of writing called the runic alphabet, or futhark, for the first six letters of the alphabet. The runes were used as both a system of writing and as a tool for fortune-telling and magic spells prior to the introduction of the Latin alphabet and Christianity. Originally, the system used 16 runes, but eight were added later.
The word "rune" comes from an old Norse word meaning "engraving." Because the tools used were primitive, the runes consist of straight lines. Each rune has a name and a letter corresponding to it. For example, the rune "ehwaz" corresponds to the letter E and looks like the Latin letter M.
The connection of runes to Norse mythology comes through Odin, the chief god of the Aesir. According to the myths, Odin hung upside-down on the world-tree that Yggdrasil pierced by a spear for nine days with no food or water. He looked down into the Well of Urd, saw the runes and took them. In the process Odin gained his famed knowledge of magic, or seidr. The runes are thought by Norse myth to be pre-existing forces, rather than a simple alphabet, but the two purposes became conflated over time.