Difficulty at once arose with reference to the right of passage of these troops, military stores, and in fact a full equipment for warlike purposes. There was not much choice of routes. Those through the Transvaal and through Bechuanaland were closed. The only route left was through the port of Beira. This course necessitated the passage of belligerent troops across two hundred miles of neutral territory controlled by Portugal as territorial sovereign. Beira, situated about four hundred and fifty miles north of Lorenzo Marques, bears nearly the same relation topographically to British Mashonaland and to British Rhodesia that Delagoa Bay does to the Transvaal and the Orange Free State. A railway nearing completion formed an almost continuous route from Beira to Salisbury in Rhodesia, and once in the latter province troops would be in a position to invade the Transvaal. Under ordinary circumstances it would have been a distinct breach of neutrality on the part of Portugal to allow the passage across her territory of the troops of one of the belligerents, since the obvious destination could only be the country of the other belligerent, with whom she was on friendly terms. Portugal had granted to England in 1896 the right of passage for a field force to be used against the natives in Mashonaland.[13] But that was a case of warfare against a savage tribe, and was not to be considered as a reliable precedent for similar action against a civilized State such as the South African Republic. [Footnote 13: Times Military History of the War in South Africa, Vol. IV p. 365] The principles of the international law of modern times leave little or no doubt as to the proper course for a neutral to follow in such a case. Oppenheim says: "In contradistinction to the practice of the eighteenth century, it is now generally recognized that a violation of the duty of impartiality is involved when a neutral allows a belligerent the passage of troops or the transport of war material over his territory. And it matters not whether a neutral give such permission to one of the belligerents only, or to both alike."[14] And Lawrence points out that "It is now acknowledged almost universally that a neutral state which permits the passage of any part of a belligerent army through its territory is acting in such a partial manner as to draw down upon itself just reprobation." The permission given of necessity "to further a warlike end" is "therefore inconsistent with the fundamental principle of state neutrality." "These considerations," he says, "have influenced practice during the present century, and the weight of modern precedent is against the grant of passage in any case."[15] [Footnote 14: International Law (1906), Vol. II, p. 345]