Then in the north of Europe, Denmark and Sweden, and later Poland, contended for or shared in the dominion of the Baltic. The Sound and the Belts fell into the possession of Denmark, the Bothnian Gulf passed under the rule of Sweden; and all the northern seas between Norway on the one hand, and the Shetland Isles, Iceland, Greenland, and Spitzbergen on the other, were claimed by Norway and later by Denmark, on the principle referred to above, that possession was held of the opposite shores. The Scandinavian claims to maritime dominion are probably indeed the most important in history. They led to several wars; they were the cause of many international treaties and of innumerable disputes about fishery, trading, and navigation; they were the last to be abandoned. Until about half a century ago Denmark still exacted a toll from ships passing through the Sound,--a tribute which at one time was a heavy burden on the trade to and from the Baltic. Still more extensive were the claims put forward by Spain and Portugal. In the sixteenth century these Powers, in virtue of Bulls of the Pope and the Treaty of Tordesillas, divided the great oceans between them. Spain claimed the exclusive right of navigation in the western portion of the Atlantic, in the Gulf of Mexico, and in the Pacific. Portugal assumed a similar right in the Atlantic south of Morocco and in the Indian Ocean. It was those preposterous pretensions to the dominion of the immense waters of the globe that caused the great juridical controversies regarding _mare clausum_ and _mare liberum_, from which modern international law took its rise. The task of Grotius in demolishing them by argument was, however, materially facilitated by the exploits of Drake, Hawkins, and Cavendish on the part of the English, and of Jakob van Heemskerk on the part of the Dutch; and, as we shall show, the credit on having first asserted the freedom of the seas in the sense now universally recognised, belongs rather to our own Queen Elizabeth than to the Dutch publicist. In thus appropriating the seas adjacent to their territories, or which formed the means of communication with them, the various nations were doubtless impelled by consideration of their own immediate interests. Sometimes it helped to secure the safety of their coasts or commerce; in other cases it enabled them to levy tribute on foreign shipping traversing the appropriated waters, and thus to increase their revenues; or it allowed them to preserve the fisheries for the exclusive use of their own subjects. In most instances, however, the principal object appears to have been to maintain a monopoly of trade and commerce as far as possible in their own hands, in accordance with the commercial spirit of the times.