From the time of Peter the Great, forms of address in the Russian Empire had been well-codified, determined by a person’s title of honor, as well as military or civil rank (see Table of Ranks) and ecclesiastical order. One’s position within the clergy was considered most important, followed by title, and then by civil/military rank (e.g., a commoner in rank of Privy Councilor would be styled His Excellency) a prince of the same rank would retain the style of His Highness, while the same prince serving as an archbishop would be referred as His High Eminence. All of these styles are now obsolete and are only used in historical context.
Grand Dukes and Grand Duchesses (i.e. Imperial children and grandchildren; from 1797 to 1886 the title applied to great- and great-great-grandchildren as well)
