The city walls, begun in 1671 and completed about 1740, were almost entirely demolished between 1863 and 1880, only a few insignificant remnants having survived the American military occupation of 1899-1902; but it is still usual to speak of the "intramural" and the "extramural" city.
Until 1898 the octroi circle did not extend beyond the walls; but in that year it was found necessary, owing to the growth of the city and of municipal expenditure, to include the external quarters or Corpi Santi (a name also applied to the extramural portions of Cremona and Pavia), with their large industrial population.
