Until the early 20th century, runes were used in rural Sweden for decorative purposes in Dalarna and on Runic calendars. However, the use of runes persisted for specialized purposes in northern Europe. The characters were generally replaced by the Latin alphabet as the cultures that had used runes underwent Christianisation, by approximately 700 AD in central Europe and 1100 AD in northern Europe. The earliest known runic inscriptions date from around 150 AD. Runology forms a specialised branch of Germanic philology. Runology is the scholastic study of the runic alphabets, runic inscriptions, runestones, and their history. The Scandinavian variants are also known as futhark or fuþark (derived from their first six letters of the alphabet: F, U, Þ, A, R, and K) the Anglo-Saxon variant is futhorc or fuþorc (due to sound-changes undergone in Old English by the names of those six letters). Examples of this are often referred to as Begriffsrunen by academics. In addition to representing a sound value (a phoneme), runes can be used to represent the concepts after which they are named ( ideographs). Runes were used to write various Germanic languages before the adoption of the Latin alphabet and for specialised purposes thereafter. Runes are the letters in a set of related alphabets known as runic alphabets. BCEĪdlam (slight influence from Arabic) 1989 CE Caucasian Albanian (origin uncertain) c.Cherokee (syllabary letter forms only) c.