Badajos in 1811 sustained a siege of more than forty days open trench.

Lerida in 1811 sustained a siege of two weeks open trench.

Saguntum in 1811 sustained a siege of a month.

Valencia in 1811-12 sustained a siege of two months

Ciudad Rodrigo in 1812 sustained a blockade of several months, and a
close siege of two weeks.

Badajos in 1812 sustained twenty-one days of open trenches.

Burgos in 1812 sustained thirty-three days of open trenches.

St. Sebastian in 1813 sustained a siege and blockade of nearly three
months, with fifty-nine days of open trenches.

Pampeluna in 1813 sustained a siege of more than four months.

Monzon in 1813-14 also sustained a siege of more than four months.

This list might be increased with numerous other examples, to show that
even poorly fortified towns are capable of defending themselves, on an
average, for more than a month. These examples, be it remembered, are
nearly all taken from a period of history since any material
improvements have been made in the art of attack. Since the time of
Vauban the improvements in attack have not kept pace with the increased
means of defence. Moreover, these examples are taken from the sieges of