The '''Book of Concord''' (1580) or Concordia (frequently called the [[Lutheran]] Confessions) is the historic doctrinal standard of the Lutheran Church, consisting of ten credal documents deemed authoritative in Lutheranism since the 16th century. | The '''Book of Concord''' (1580) or Concordia (frequently called the [[Lutheran]] Confessions) is the historic doctrinal standard of the Lutheran Church, consisting of ten credal documents deemed authoritative in Lutheranism since the 16th century. |