The history of the relations of Denmark and the Duchies to the Romano-Germanic Empire is a very small part of the great Schleswig-Holstein controversy. But having been unnecessarily mixed up with two questions properly quite distinct,--the first, as to the relation of Schleswig to Holstein, and of both jointly to the Danish crown; the second, as to the diplomatic engagements which the Danish kings have in recent times contracted with the German powers,--it has borne its part in making the whole question the most intricate and interminable that has vexed Europe for two centuries and a half. Setting aside irrelevant matter, the facts as to the Empire are as follows:-- I. The Danish kings began to own the supremacy of the Frankish Emperors early in the ninth century. Having recovered their independence in the confusion that followed the fall of the Carolingian dynasty, they were again subdued by Henry the Fowler and Otto the Great, and continued tolerably submissive till the death of Frederick II and the period of anarchy which followed. Since that time Denmark has been always independent, although her king was, until the treaty of A.D. 1865, a member of the German Confederation for Holstein. II. Schleswig was in Carolingian times Danish; the Eyder being, as Eginhard tells us, the boundary between Saxonia Transalbiana (Holstein), and the Terra Nortmannorum (wherein lay the town of Sliesthorp), inhabited by the Scandinavian heathen. Otto the Great conquered all Schleswig, and, it is said, Jutland also, and added the southern part of Schleswig to the immediate territory of the Empire, erecting it into a margraviate. So it remained till the days of Conrad II, who made the Eyder again the boundary, retaining of course his suzerainty over the kingdom of Denmark as a whole. But by this time the colonization of Schleswig by the Germans had begun; and ever since the numbers of the Danish population seem to have steadily declined, and the mass of the people to have grown more and more disposed to sympathize with their southern rather than their northern neighbours. III. Holstein always was an integral part of the Empire, as it is at this day of the North German Bund. NOTE C. ON CERTAIN IMPERIAL TITLES AND CEREMONIES. This subject is a great deal too wide and too intricate to be more than touched upon here. But a few brief statements may have their use; for the practice of the Germanic Emperors varied so greatly from time to time, that the reader becomes hopelessly perplexed without some clue. And if there were space to explain the causes of each change of title, it would be seen that the subject, dry as it may appear, is very far from being a barren or a dull one. I. TITLES OF EMPERORS. Charles the Great styled himself 'Carolus serenissimus Augustus, a Deo coronatus, magnus et pacificus imperator, Romanum (_or_ Romanorum) gubernans imperium, qui et per misericordiam Dei rex Francorum et Langobardorum.'