He was known for the purity and austerity of his life. When the Emperor Leo VI married a fourth time (his three previous wives having died), the Patriarch barred him from the church. The Emperor sent the Patriarch into exile and had his marriage approved by delegates of the Roman Pope. When the Emperor died, Nicholas was restored to the Patriarchal throne, and called a Council in 925, at which fourth marriages were forbidded in the Church under any circumstance. He died peacefully.   The title Mystikos was given to some high-ranking members of the Imperial council (perhaps because they met in secret). The Patriarch was a courtier with this title before he forsook the world and was tonsured a monk.   Note: From early times, the Eastern and Latin churches have differed in their views on marriage. The Latin church held, and still holds, that marriage is dissolved by death, so in theory any number of re-marriages is permissible (a view that the Emperor Leo sought to exploit). The Eastern Church has traditionally been uncomfortable with any second marriage — some of the Fathers even call the re-marriage of widows or widowers "bigamy". Still the Eastern church tolerates re-marriage (even after divorce) as a concession for the salvation of those who cannot sustain the single state.