The tuning (my son-in law guitarist calls it an 'open d') is said to come from the piece, "The Siege of Sevastopol,"
but others cite older occurrences. Can any be cited?

A "Siege of Seb(v)astopol Polka" was written in 1855, piano, but I have not found any guitar or other music with the title "The Siege of Sev(b)astopol" except the reference: "a mood piece found in 19th century instructors for parlor guitar" (Mark Wilson). Entry in Fiddlers Companion. AKA Vasapol, Vestapol. Anyone have one of these old 19th c. instructors?

There is a Sebastopol Hornpipe, widely used by many fiddlers, but its origin not stated in the Fiddlers Companion. Assumed Crimean War vintage.