Leo XII: "No human law can abolish the natural and original right of marriage"

"No human law can abolish the natural and original right of marriage, nor in any way limit the chief and principal purpose of marriage ordained by God's authority from the beginning: "Increase and multiply." Hence we have the family, the "society" of a man's house -- a society very small, one must admit, but none the less a true society, and one older than any State. Consequently, it has rights and duties peculiar to itself which are quite independent of the State."

-- Leo XII Rerum Novarum, (12), MAY 15, 1891