Why did john de courcy leave Dublin?

John de Courcy left Dublin primarily due to political and social unrest in Ireland during the late 12th century. As a Norman knight, he sought to establish his power and influence in the province of Ulster, which was less politically stable than Dublin. His ambitions were driven by opportunities for land and wealth, as well as the desire to expand Norman control in Ireland. This move ultimately led to his significant role in the Norman invasion of Ireland.