...The earlier crosses were typically up to about two metres or eight feet high, but in Ireland examples up to three times higher appear later, retaining thick massive proportions, giving large surface areas for carving. Anglo-Saxon examples mostly remained slender in comparison, but could be large; except in earlier Northumbrian examples their decoration is mostly ornamental rather than figures. The crosses often, though not always, feature a stone ring around the intersection, forming a Celtic cross; this seems clearly an innovation of Celtic Christianity, perhaps at Iona.[2] The term "high cross" is mainly used in Ireland and Scotland, but the tradition across the whole of the British Isles, is essentially a single phenomenon, though there are certainly strong regional variations.
Some crosses were erected just outside churches and monasteries; others at sites that may have marked boundaries or crossroads, or preceded churches. Whether they were used as "preaching crosses" at early dates is unclear, and many crosses have been moved to their present locations. They do not seem to have been used as grave-markers in the early medieval period. In the 19th century Celtic Revival Celtic crosses with decoration in a form of Insular style, became very popular as gravestones and memorials, and are now found in many parts of the world. Unlike the Irish originals, the decoration usually does not include figures....
