The Pauline Laws are the house laws of the House of Romanov of the Russian Empire. The name comes from the fact that they were initially established by Emperor Paul I of Russia in 1797.
Paul I abolished Peter the Great's law which allowed each reigning emperor or empress to designate his or her successor, substituting a strict order of succession by proclaiming that the eldest son of the monarch shall inherit the throne, and other dynasts according to primogeniture in the male-line. In so doing, Paul implemented a semi-Salic line of succession to the Russian Throne: The throne could henceforth pass to a female and through the female (cognatic) line of the dynasty, upon the extinction of all legitimately-born, male dynasts.
Over time the house laws were amended, and in the late Russian Empire the laws governing membership in the imperial house, succession to the throne and other dynastic subjects were divided, some being included in the Fundamental Laws of the Russian Empire and others in the Statute of the Imperial Family (codification of 1906, as amended through 1911).
In the spring of 1911, Princess Tatiana Konstantinovna of Russia became engaged to Prince Konstantin Alexandrovich Bagration-Mukhransky (1889 - 1915), a Georgian by birth, serving in a Russian Imperial Guards regiment, who would die in World War I. She was to be the first daughter of the Romanovs to openly marry a Russian subject or non-dynastic prince since the Romanov dynasty ascended the throne in 1613. Her anxious father approached the Emperor Nicholas II and his empress, Alexandra Fyodorovna of Hesse, for approval. On 30 November 1910 Grand Duke Constantine Konstantinovich noted in one of his posthumously published journals ("From the Diaries of Grand Duke Konstantin Konstantinovich", Moscow, February 1994), that he had received assurances that "they would never look upon her marriage to a Bagration as morganatic, because this House, like the House of Orléans, is descended from a once ruling dynasty."