This is called a Cathedra
A Cathedral is so named because it holds the official seat or throne or cathedra (Latin) of the Bishop, thus the Cathedral is the Bishop’s Church. Just as all priests are united to the bishop through his apostolic authority, so all churches are united to the cathedral which gives her the moniker of the Mother Church.
As the Mother Church, the Cathedral often holds diocesan events including ordinations, celebrations, and conferences. It is the mantle of the Cathedral to help support and strengthen the churches in the diocese and to pray for them regularly.