In the days of Roman dominion, a city called Civitas Ubiorum was built by the Rhine upon the site where now stands the fortified mediæval town of Cologne. Remains of the Roman occupation are still to be traced in the city in the bases of walls, but the amphitheatre was demolished long ago. Agrippina was born here, and Trajan ruled in the fortress. In the Middle Ages Cologne was a prosperous city, with a wide trading repute, and celebrated for its arts and learning. William Caxton came here to learn printing, an industry which he introduced into England. Militarism and clerical domination appear to have been the chief causes of the long spell of misfortune that fell later upon Cologne. Persecution was one of the principal occupations of a number of the people at this period; and much zeal was expended in expelling heretics, Jews and Protestants from the city. Cologne also suffered decline through the closing of the Rhine as a navigable waterway by the Dutch, and it was not until 1837 that the river was re-opened to trading vessels plying to foreign ports. To-day the city is an important commercial and industrial centre. Perhaps the best general view of Cologne is from the opposite bank of the Rhine. The city is a forest of spires and towers; there were at one time over two thousand clerics within the walls, and religious buildings were more numerous then than to-day. The wide river is spanned by two bridges; the more important is a wonderful structure, over thirteen hundred feet in length, and made of iron. The Cathedral was begun in the thirteenth century, but it remained for a considerable time in an unfinished state, and portions fell into decay. Frederick William III. restored the building, and added to it; and since this time the work has been continued in several parts of the edifice. Externally the Cathedral is a stately building with its flying buttresses, host of pinnacles, and splendid south doorway. The architecture is French--rather German--Gothic. [Illustration: COLOGNE. ST. MARTIN'S CHURCH, 1826.] In the choir are very brilliant stained windows, some mural pictures, and numerous statues of Scriptural characters. The painted windows here, and in the aisles, are extremely gorgeous examples of this art. Among the objects of interest in the chapels are memorials of the archbishops of the city, and an early painting, known as the Dombild, depicting the saints of Cologne. The Church of St Ursula and of the Eleven Thousand Virgins is remarkable for its treasury of the bones of the adventurous virgins of the famous legend. These relics are embedded in the walls of the choir. There are a few pictures, but none of note, in this church.