{{not verified}} St. Machar is believed to be a sixth-century Irish missionary active on the Isle of Mull and perhaps eastern Scotland. His existence and identity, however, have long been queried.
Legend claims that Machar was a son of Fiachna, Prince of Ulster (not the ancient Fiachna, High King of Ireland) and that he was given the name Mochumma when baptised as a young man by St. Colman of Kilmacduagh (Colman MacDuagh). He was supposedly one of the group of twelve men who accompanied St. Columba from Ireland into exile on Iona in 561, where they established the monastery that became the centre for Christian missionary work in Scotland and northern England. Machar is said to have worked mostly on the neighbouring Isle of Mull, but that the miracles he wrought there made others envious and Columba was asked to send him elsewhere. Columba supposedly told Machar to take their mission to the Pictish people of eastern Scotland, founding a church "where a river formed the shape of a crosier".
The precision of this purported instruction has meant that more than one place in eastern Scotland has been proposed as the site where Machar founded a church. One is the site of St. Machar's Cathedral, Aberdeen; another is a site near Aboyne where it is claimed Machar established a cell. Three features in the area are named after him: St. Machar's Well, St. Machar's Cross (a boulder into which a cross has been cut) and a rock known as St. Machar's Chair (the Cathair Mochrieha; "Mochrieha" is another version of Machar/Mochumma's name).
There is, however, no mention of Machar, Mochumma or Mochrieha in the ancient biographies of St. Columba that survive. In particular, no mention of him is made in the life of St. Columba written by St. Adomnán (Adamnán), an abbot of the Iona monastery who would have had contact with monks who had known Columba and his followers. Adomnán does not list Machar (or Mochumma, or Mochrieha) as one of the twelve who accompanied Columba into exile; nor does he or any other sources from the period mention the story that Machar supposedly accompanied Columba on a journey to visit Pope Gregory I.
On the other hand, much of what is claimed to be known about St. Machar derives from the Aberdeen Breviary, a Roman Catholic work compiled in the late fifteenth to early sixteenth centuries, long after Machar's supposed existence. By then the Roman Catholic church was well-established in Scotland and wished to play down or even conceal the role of non-Roman missionaries such as Columba and Machar. Information from such sources, therefore, needs to be treated with caution.
One recent theory is that St. Machar and St. Mungo were the same person, on the grounds of a possible link between their names (Colm Ó Baoill, St. Machar - some linguistic light?, Innes Review XLIV, p.1-13).