Iglesia matriz
The mother church in Christian Science is The First Church of Christ, Scientist in Boston, the Church of Christ Scientist of which all others are branches. Per the "Manual of The Mother Church", the legal title of the mother church is "The First Church of Christ, Scientist," and while its branch churches may call themselves First Church of Christ, Scientist, or Second Church of Christ, Scientist, etc., they are prohibited from using "The" in front of their names. Only The Mother Church can do so.