First Princes' War

The First Princes' War, also referred to as the First Vicarial War, was a series of interlocked civil conflicts in the Kingdom of the Fhainn that lasted from June 1519 to January 1545. It began over a dispute over the rights of vassal lords within the Kingdom and later expanded to a war over succession to the Chathairrih Fhainn by Clyde Barheln through his marriage to the Rih 's sister, Bronwyn. It consisted of three distinct phases - the Eastern Campaign, the Protestant Wars, and the Succession War. Depending on the source, it is also described as being either a direct cause of or the parent conflict of the Kurikilan Crusade.

Succession
The succession of the war at its beginning was not in dispute, as the throne clearly passed to the oldest son of Ruaridh III, Caerls. However, after his early death in the war, the throne was claimed by Clyde Barheln, a choice supported by Protestant lords who were willing to overlook Caerls' cousin, Rhys Wydd-Màrtainn, in favor of Clyde, a fellow Protestant.