Excommunication is a formal exclusion from participation in the sacraments and services of the Christian Church, which signifies that a person is no longer in communion with the Church. This act can result from various offenses, including heresy, grave sin, or dissent against Church authority, and serves both as a disciplinary measure and a spiritual warning. During medieval times, excommunication often had significant social and political repercussions, especially in the context of Church-state relations.