1772: 12 Geo 3 c. 11: An Act for the better regulating the future Marriages of the Royal Family.
Most Gracious Sovereign,
Whereas your Majesty, from your paternal affection to your own family, and from your royal concern for the future welfare of your people, and the honour and dignity of your crown, was graciously pleased to recommend to your parliament to take into serious consideration, whether it might not be wise and expedient to supply the defect of the laws now in being; and, by some new provision, more effectually to guard the descendants of His late majesty King George the Second, (other than the issue of princesses who have married, or may hereafter marry, into foreign families) from marrying without the approbation of your Majesty, your heirs, or successors, first had and obtained; we have taken this weighty matter into our serious consideration; and, being sensible that marriages in the royal family are of the highest importance to the state, and that therefore the Kings of this realm have ever been entrusted with the care and approbation thereof; and, being thoroughly convinced of the wisdom and expediency of what your Majesty has thought fit to recommend, upon this occasion, we, your Majesty’s most dutiful and loyal subjects the lords spiritual and temporal, and commons, in this present parliament assembled, do humbly beseech your Majesty that it may be enacted: and be it enacted by the King’s most excellent majesty, by and with the advice and consent of the lords spiritual and temporal, and commons, in this present parliament assembled, and by the authority of the same,
That no descendant of the body of his late majesty King George the Second, male or female, (other than the issue of princesses who have married, or may hereafter marry, into foreign families) shall be capable of contracting matrimony without the previous consent of his Majesty, his heirs, or successors, signified under the great seal, and declared in council, (which consent, to preserve the memory thereof is hereby directed to be set out in the licence and register of marriage, and to be entered in the books of the privy council); and that every marriage, or matrimonial contract, of any such descendant, without such consent first had and obtained, shall be null and void, to all intents and purposes whatsoever.
II. Provided always, and be it enacted by the authority aforesaid, That in case any such descendant of the body of his late majesty King George the Second, being above the age of twenty-five years, shall persist in his or her resolution to contract a marriage disapproved of or dissented from, by the King, his heirs, or successors; that then such descendant, upon giving notice to the King’s privy council, which notice is hereby directed to be entered in the books thereof, may, at any time from the expiration of twelve calendar months after such notice given to the privy council as aforesaid, contract such marriage; and his or her marriage with the person before proposed, and rejected, may be duly solemnized, without the previous consent of his Majesty, his heirs, or successors; and such marriage shall be good, as if this act had never been made, unless both houses of parliament shall, before the expiration of the said twelve months, expressly declare their disapprobation of such intended marriage.
III. And be it further enacted by the authority aforesaid, That every person who shall knowingly or wilfully presume to solemnize, or to assist, or to be present at the celebration of any marriage with any such descendant, or at his or her making any matrimonial contract, without such consent as aforesaid first had and obtained, except in the case above-mentioned, shall, being duly convicted thereof incur and suffer the pains and penalties ordained and provided by the statute of provision and premunire made in the sixteenth year of the reign of Richard the Second.
Further reading: Wikipedia.