There is a valuable article on ancient trade in Encyclopaedia Biblica, IV., 48, etc. H. H. Helmolt, General History, VII., pt. i., pp. 1- 139, has a long and valuable chapter on "The Economic Development of Western Europe Since the Time of the Crusades," by Dr. Richard Mayr.
Several general histories of Europe covering the field of this volume have been published in recent years or are now appearing. I. and VII. Helmolt differs from all other general histories by its arrangement in accordance with ethnographical and geographical divisions rather than historical epochs; he pays also especial attention to economic phenomena.