Sedevacantism (Latin: Sedevacantismus) is a doctrinal position within traditionalist Catholicism, which holds that the present occupier of the Holy See is not a valid pope due to the Pope's espousal of one or more heresies and that, for lack of a valid pope, the See of Rome is vacant.
The term sedevacantism is derived from the Latin phrase sede vacante, which means "with the chair [i.e. of the Bishop of Rome] being vacant". The phrase is commonly used to refer specifically to a vacancy of the Holy See from the Pope's death or resignation, to the election of his successor.
Among sedevacantist, some chose to end the vacancy in the Holy See by electing their own pope; hence, they are more appropriately called conclavists.The number of sedevacantists is unknown and difficult to measure; estimates range from tens of thousands to hundreds of thousands.
Positions
Origin
Sedevacantism owes its origins to the rejection of the theological and disciplinary changes implemented following the Second Vatican Council (1962...