Proper introductions were important to Victorians, as it was generally considered improper to address someone to whom you hadn't been formally presented. Social inferiors were presented to social superiors in an introduction, with the exception that ladies were always introduced to gentlemen regardless of rank.
So to introduce people as a proper Victorian, you had to know your social rankings, or the order of precedence. This was no easy task to keep straight. After the sovereign and the sovereign's close relations came the Archbishop of Canterbury and Lord High Chancellor and so on. Titled nobility included two orders: the peerage (which included dukes, marquesses, earls, viscounts and barons, in that order) and, below them, baronets and knights.
Properly addressing such nobility was also difficult. Generally, one used "Lord" to address peers, "Lady" to address women married to a peer, and "Sir" to address baronets and knights. Making it more confusing, however, was the use of "lord" and "lady" to address upper-class people who were not nobility (as a "courtesy title") [source: Pool]. This was also opposed to written communication, because one had to know that a marquis was addressed as "The Most Noble" but other peers were addressed as "The Right Honorable" [source: Pool].