The degrees of Mark Master Mason and Royal Arch Mason are complimentary to membership of the Freemasons and have for centuries been considered an essential though separate part of the Masonic Order.

Mark and Royal Arch Explained
Throughout the 18th Century, many Masonic Lodge had been conferring degrees of membership beyond those allowed by Grand Lodge. These degrees had spread across the globe along with the spread of the Fraternity in Ireland, by the early 19th Century, it was agreed to allow these extra degrees to continue as separate fraternities, open to Freemasons.

The degree of Mark Master Mason is conferred in a Lodge of Mark Master Masons while separately; the Degree of Royal Arch Mason is conferred in Royal Arch Chapters.

Within the Irish Masonic structure, both Mark and Royal Arch are governed by the Grand Royal Arch Chapter.