On the 7th of June, 1840, Frederick William III. of Prussia died, and was succeeded by his son Frederick William IV., a religious and patriotic king, who was compelled to make promises for some sort of constitutional liberty, and to grant certain concessions, which although they did not mean much gave general satisfaction. Among other things the freedom of the Press was partially guaranteed, with certain restrictions, and the Zollverein was extended to Brunswick and Hesse-Homburg. Meantime the government entered with zeal upon the construction of railways and the completion of the Cathedral of Cologne, which tended to a more permanent union of the North German States. "We are not engaged here," said the new monarch, on the inauguration of the completion of that proudest work of mediaeval art, "with the construction of an ordinary edifice; it is a work bespeaking the spirit of union and concord which animates the whole of Germany and all its persuasions, that we are now constructing." This inauguration, amid immense popular enthusiasm, was soon followed by the meeting of the Estates of the whole kingdom at Berlin, which for the first time united the various Provincial Estates in a general Diet; but its functions were limited to questions involving a diminution of taxation. No member was allowed to speak more than once on any question, and the representatives of the commons were only a third part of the whole assembly. This naturally did not satisfy the nation, and petitions flowed in for the abolition of the censorship of the Press and for the publicity of debate. The king was not prepared to make these concessions in full, but he abolished the censorship of the Press as to works extending to above twenty pages, and enjoined the censors of lesser pamphlets and journals to exercise gentleness and discretion, and not erase anything which did not strike at the monarchy. At length, in 1847, the desire was so universal for some form of representative government that a royal edict convoked a General Assembly of the Estates of Prussia, arranged in four classes,--the nobles, the equestrian order, the towns, and the rural districts. The Diet consisted of six hundred and seventy members, of which only eighty were nobles, and was empowered to discuss all questions pertaining to legislation; but the initiative of all measures was reserved to the crown. This National Diet assembled on the 24th of July, and was opened by the king in person, with a noble speech, remarkable for its elevation of tone. He convoked the Diet, the king said, to make himself acquainted with the wishes and wants of his people, but not to change the constitution, which guaranteed an absolute monarchy. The province of the Diet was consultative rather than legislative. Political and military power, as before, remained with the king. Still, an important step had been taken toward representative institutions.