A Celtic script used for writing in northwest Europe, probably created in the 2nd-3rd centuries AD, and used for writing Irish and Pictish languages. The alphabet has 20 letters represented by tally marks on either side of or crossing a horizontal baseline. The script is better suited for carving on stone (or possibly wood) than for writing in ink. It is believed to have originated in Ireland or south Wales as a secret script and it spread throughout the Celtic areas for use on memorial stones. It is also found associated with the symbols and carvings of the Picts, who used it till the 9th century. Ogham is used on memorial pillar stones in the Celtic regions of Britain, usually consisting of no more than the name and descent of the dead man. It was often the custom, particularly in the south and west in Wales and Cornwall, to provide a translation in Latin minuscule and this has proved important for the translation and dating of ogham. Of the more than 375 ogham inscriptions known, about 300 are from Ireland.