Ogham inscription

Roughly 400 known ogham inscriptions are on stone monuments scattered around the Irish Sea, the bulk of them dating to the fifth and sixth centuries. Their language is predominantly Primitive Irish, but a few examples record fragments of the Pictish language. Ogham itself is an Early Medieval form of alphabet or cipher, sometimes known as the "Celtic Tree Alphabet".
A number of different numbering schemes are used. The most widespread is CIIC, after R. A. S. Macalister ("Corpus Inscriptionum Insularum Celticarum", Latin for "corpus of Insular Celtic inscriptions"). This covers the inscriptions known by the 1940s. Another numbering scheme is that of the Celtic Inscribed Stones Project, CISP, based on the location of the stones; for example CIIC 1 = CISP INCHA/1. Macalister's (1945) numbers run from 1 to 507, including also Latin and Runic inscriptions, with three additional added in 1949. Ziegler lists 344 Gaelic ogham inscriptions known to Macalister (Ireland and Isle of Man), and seven additional inscriptions discovered later.
The inscriptions may be divided into "orthodox" and "scholastic" specimens. "Orthodox" inscriptions date to the Primitive Irish period, and record a name of an individual, either as a cenotaph or tombstone, or documenting land ownership. "Scholastic" inscriptions date from the medieval Old Irish period up to modern times.
The vast bulk of the surviving ogham inscriptions stretch in arc from County Kerry (especially Corcu Duibne) in the south of Ireland across to Dyfed in south Wales. The remainder are mostly in south-eastern Ireland, eastern and northern Scotland, the Isle of Man, and England around the Devon/Cornwall border. The vast majority of the inscriptions consists of personal names, probably of the person commemorated by the monument.
Orthodox inscriptions.
In orthodox inscriptions, the script was carved into the edge ("droim" or "faobhar") of the stone, which formed the stemline against which individual characters are cut. The text of these "Orthodox Ogham" inscriptions is read beginning from the bottom left side of a stone, continuing upward along the edge, across the top and down the right side (in the case of long inscriptions).
MacManus (1991) lists a total of 382 known Orthodox inscriptions. They are found in most counties of Ireland but are concentrated in southern Ireland, with the highest numbers found in County Kerry (130), Cork (84), and Waterford (48). Other counts are as follows: Kilkenny (14); Mayo (9); Kildare (8); Wicklow and Meath (5 each); Carlow (4); Wexford, Limerick, and Roscommon (3 each); Antrim, Cavan, Louth, and Tipperary (2 each); Armagh, Dublin, Fermanagh, Leitrim, Londonderry and Tyrone (1 each). 
Other specimens are known from Wales (ca. 40: Pembrokeshire (16); Breconshire and Carmarthenshire (7 each); Glamorgan (4); Cardiganshire (3); Denbighshire (2); Powys (1), and Caernarvonshire (1)). A few are known of from sites in Englan, such as Cornwall (5), Devon (2), and the Isle of Man (5), and some doubtful examples from Scotland (possibly 2).
Formula words.
The vast majority of inscriptions consists of personal names and use a series of formula words, usually describing the person's ancestry or tribal affiliation. 
Formula words used include the following: 
In order of frequency, the formula words are used as follows:
Nomenclature.
The nomenclature of the Irish personal names is more interesting than the rather repetitive formulae and reveals details of early Gaelic society, particularly its warlike nature. 
For example, two of the most commonly occurring elements in the names are CUNA – 'hound' or 'wolf' (Modern Irish "cú") and CATTU – 'battle' (Modern Irish "cath").
These occur in names such as (300) CUNANETAS – 'Champion of wolves'; (501) CUNAMAGLI – 'prince of wolves'; (107) CUNAGUSSOS – '(he who is) strong as a wolf'; (250) CATTUVVIRR – 'man of battle'; (303) CATABAR – 'chief in battle'; IVACATTOS – 'yew of battle'. 
Other warlike names include (39) BRANOGENI – 'born of raven'; (428) TRENAGUSU – 'strong of vigour'; and (504) BIVAIDONAS – 'alive like fire'.
Elements that are descriptive of physical characteristics are also common, such as (368) VENDUBARI – 'fair-headed'; (75) CASONI – 'curly headed one'; (119) DALAGNI – 'one who is blind'; (46) DERCMASOC – 'one with an elegant eye'; (60) MAILAGNI – 'bald/short haired one' and (239) GATTAGLAN – 'wise and pure'.
Other names indicate a divine ancestor. The god Lugh features in many names such as (4) LUGADDON , (286) LUGUDECA and (140) LUGAVVECCA , while the divine name ERC (meaning either 'heaven or 'cow') appears in names such as (93) ERCAIDANA and (196) ERCAVICCAS . 
Other names indicate sept or tribal name, such as (156) DOVVINIAS from the "Corcu Duibne" sept of the Dingle and Iveragh peninsulas in Co. Kerry (named after a local goddess); (215) ALLATO from the "Altraige" of North Kerry and (106) CORIBIRI from the "Dál Coirpri" of Co. Cork. 
Of particular interest is the fact that quite a few names denote a relationship to trees, such as (230) MAQI-CARATTINN – 'son of rowan'; (v) MAQVI QOLI – 'son of hazel' and (259) IVOGENI – 'born of yew'.
The content of the inscriptions has led scholars such as McNeill and Macalister to argue that they are explicitly pagan in nature. They argue that the inscriptions were later defaced by Christian converts, who deliberately removed the word MUCOI on account of its supposedly pagan associations and added crosses next to them. 
Other scholars, such as McManus, argue that there is no evidence for this, citing inscriptions such as (145) QRIMITIR RONANN MAQ COMOGANN , where QRIMITIR is a loan word from Latin "presbyter" or 'priest'. McManus argues that the supposed vandalism of the inscriptions is simply wear and tear, and due to the inscription stones being reused as building material for walls, lintels, etc. (McManus, §4.9). McManus also argues that the MUCOI formula word survived into Christian manuscript usage. There is also the fact the inscriptions were made at a time when Christianity had become firmly established in Ireland. Whether those who wrote the inscriptions were pagans, Christians, or a mixture of both remains unclear.
Ireland.
Ireland has the vast majority of inscriptions, with 330 out of 382. One of the most important collections of orthodox ogham inscriptions in Ireland can be seen in University College Cork (UCC) on public display in 'The Stone Corridor'. The inscriptions were 
collected by antiquarian Abraham Abell 1783–1851 and were deposited in the Cork Institution before being put on display in UCC. He was a member of the Cuvierian Society of Cork whose members, including John Windele, Fr. Matt Horgan and R.R. Brash, did extensive work in this area in the mid-19th century. 
Another well-known group of inscriptions, known as the Dunloe Ogham Stones, can be seen at Dunloe near Killarney in Co. Kerry. The inscriptions are arranged in a semicircle at the side of the road and are very well preserved.
Wales.
The orthodox inscriptions in Wales are noted for containing names of both Latin and Brythonic (or early Welsh) origin, and are mostly accompanied by a Latin inscription in the Roman alphabet (Ecclesiastical and Late Latin remained the language of writing in Wales throughout the post-Roman period). Examples of Brythonic names include (446) MAGLOCUNI (Welsh "Maelgwn") and (449) CUNOTAMI (Welsh "cyndaf"). 
Wales has the distinction of the only ogham stone inscription that bears the name of an identifiable individual. The stone commemorates Vortiporius, a 6th-century king of Dyfed (originally located in Clynderwen). Wales also has the only ogham inscription known to commemorate a woman. At Eglwys Cymmin (Cymmin church) in Carmarthenshire is the inscription (362) AVITORIGES INIGENA CUNIGNI or 'Avitoriges daughter of Cunigni'. Avitoriges is an Irish name while Cunigni is Brythonic (Welsh "Cynin"), reflecting the mixed heritage of the inscription makers. Wales also has several inscriptions which attempt to replicate the supplementary letter or forfeda for P (inscriptions 327 and 409). 
England, Isle of Man, Scotland.
England has seven or eight ogham inscriptions, five in Cornwall and two in Devon, which are the product of early Irish settlement in the area (then the Brythonic kingdom of Dumnonia). A further inscription in Silchester in Hampshire is presumed to be the work of a lone Irish settler. 
Scotland has only three orthodox inscriptions, as the rest are scholastic inscriptions made by the Picts (see below). 
The Isle of Man has five inscriptions. One of these is the famous inscription at Port St. Mary (503) which reads DOVAIDONA MAQI DROATA or 'Dovaidona son of the Druid'.
Scholastic inscriptions.
The term 'scholastic' derives from the fact that the inscriptions are believed to have been inspired by the manuscript sources, instead of being continuations of the original monument tradition. Scholastic inscriptions typically draw a line into the stone's surface along which the letters are arranged, rather than using the stone's edge. They begin in the course of the 6th century, and continue into Old and Middle Irish, and even into Modern times. From the High Middle Ages, contemporary to the Manuscript tradition, they may contain Forfeda. The 30 or so Pictish inscriptions qualify as early Scholastic, roughly 6th to 9th century. Some Viking Age stones on Man and Shetland are in Old Norse, or at least contain Norse names.