The Aghascrebagh ogham stone

The Aghascrebagh ogham stone near Greencastle in the Sperrins. The stone is believed to have been erected around 300-400AD. It is one of the only examples of Ogham writing - an early Irish alphabet - in Ulster. Linear incisions on the side of the stone read from bottom to top reveal the stone was a burial monument for one Dotetto Maqi Maglani.
'Maqi' is an old form of the modern Irish 'Mac' - 'son of' - indicating the stone was erected for 'Dotetto, son of Maglani,' referencing two men who lived in the area over 1,500 years ago. It is one of the earliest examples of writing in Ireland. 'Aghascrebagh' means 'the field of writing'.