This essay traces the published roots of the components of Irish begrudgery in early Irish literature ( Táin Bó Cúailnge and other ancient Irish myths) and Brehon legal tracts (such as the Senchus Mór and The Book of Aicill) . First, the power of language in a predominantly oral culture is explored through examples like cursing and the peculiarly Irish type of satirist. A brief explanation of the functioning and history of Brehon law is provided, and the connections between Brehon law, literature and begrudgery are considered. Begrudgery is then tied to Nietzsche’s theory of ressentiment as both are distinguished primarily by a concern and involvement with power. While the elimination of Brehon law cannot be linked directly to the rise in begrudgery, the two events emerged from the same... historical conditions. It was British colonialism that removed Brehon law from Irish society, just as the long colonial period offered a perfect environment for a sentiment like begrudgery to flourish as a widespread social phenomenon. So, while the apparatuses of begrudgery existed well before the English invasion, and although examples of early begrudgers can be found in ancient Irish literature, it was the colonial period that gave birth to modern Irish begrudgery.