Equally important was the action of the government in developing foreign trade. The first step was the inclusion of Hamburg and Bremen in the _Zollverein_; this was necessary if German maritime enterprise was to become a national and not merely a local concern, for the two Hansa cities practically controlled the whole foreign trade and owned three-quarters of the shipping; but so long as they were excluded for the Customs Union their interests were more cosmopolitan than national. Both cities, but especially Hamburg, were very reluctant to give up their privileges and the commercial independence which they had enjoyed almost since their foundation. As a clause in the constitution determined that they should remain outside the Customs Union until they voluntarily offered to enter it, there was some difficulty in overcoming their opposition. Bismarck, with characteristic energy, proposed to take steps, by altering the position of the imperial customs stations, which would practically destroy the commerce of Hamburg, and some of his proposals which seemed contrary to the constitution aroused a very sharp resistance in the Bundesrat. It was, however, not necessary to go to extremities, for in 1881 the senate of Hamburg accepted an agreement which, after a keen struggle, was ratified by the citizens. By this Hamburg was to enter the _Zollverein_; a part of the harbour was to remain a free port, and the empire contributed two million pounds towards rearranging and enlarging the harbour. A similar treaty was made with Bremen, the free port of that city being situated near the mouth of the Weser at Bremerhaven; and in 1888, the necessary works having been completed, the cities entered the Customs Union. They have had no reason to regret the change, for no part of the country profited so much by the great prosperity of the following years, notwithstanding the temporary check caused by the serious outbreak of cholera at Hamburg in 1892. Colonies. During the first years of the empire Bismarck had occasionally been asked to interest himself in colonial enterprise. He had refused, for he feared that foreign complications might ensue, and that the country might weaken itself by dissipation of energy. He was satisfied that the Germans should profit by the commercial liberty allowed in the British colonies. Many of the Germans were, however, not contented with this, and disputes regarding the rights of German settlers in Fiji caused some change of feeling. The acquisition of German colonies was really the logical and almost necessary sequel of a protective policy. For that reason it was always opposed by the extreme Liberal party.