Amid such alternations of fortune the growth of Vienna was necessarily slow. In 1714, after six centuries of existence, its population amounted to only 130,000. The city retained all the characteristics of a fortress and frontier-post. The old part, or core, now called the "inner town," was a compact body of houses surrounded by massive fortification-walls and a deep moat. Outside of this was a _rayon_ or clear space six hundred feet in width, separating the city from the suburbs. These suburbs, Leopoldstadt, Mariahilf, etc., now incorporated with the inner city in one municipal government, were then small detached villages. From time to time the rayon was encroached upon by enterprising builders, with the connivance of the emperor or the garrison commander. The disastrous wars with France at the end of the last century and beginning of the present were in reality a gain to Vienna. Napoleon's bombardment and capture of the city in 1809, before the battle of Wagram, demonstrated conclusively that the fortifications were unable to withstand modern artillery. Accordingly, after the general European peace had been established by the Congress of Vienna, the city was declared officially by the emperor to be no longer a fortification. But the walls and ditch, so far as they had not been injured by the French, were still suffered to remain: they were substantially intact as late as 1848, and were strong enough to enable the revolutionists who had possession of the city to hold it for forty-eight hours against the army of Prince Windischgrätz.