by an attack from
the rear (through the disclosure of a secret path by a renegade in the
Persian service), the resistance offered to the "invincible" Persians
emboldened the Greeks in their future encounters, and led to the
ultimate defeat of the invaders. According to the legendary history of
Rome, Horatius Cocles and two companions defended the _Sublician
Bridge_ over the Tiber against Lars Porsena and the whole army of the
Etruscans. This legendary heroism was equalled or surpassed during the
_Second Battle of the Somme_ (March 21, 1918). "The bridges across the
Crozat and Somme Canals were destroyed, though in some cases not with
entire success, it being probable that certain of them were still
practicable for infantry. Instances of great bravery occurred in the
destruction of these bridges. In one case, when the electrical
connection for firing the demolition charge had failed, the officer
responsible for the destruction of the bridge personally lit the
instantaneous fuse and blew up the bridge. By extraordinary good
fortune he was not killed" (Sir D. Haig's Dispatches). At _Rorke's
Drift_ (January 22, 1879) a force of 80 other ranks of the 24th
Regiment, under Lieutenants Chard and Bromhead, with about 40 hospital
cases, drove off the repeated attacks of 4,000 Zulus, part of
Cetewayo's army which had surprised and annihilated the garrison {78}
at _Isandhlwana_ earlier the same day. An astounding feat of arms was
performed by a small body of troops during the withdrawal of the
British Army in face of the overwhelming German attack at the _Second
Battle of the Somme_. A detachment of about 100 officers and men of
the 61st Brigade, 20th Division, was detailed to cover the withdrawal
of their division at _Le Quesnoy_ (March 27,1918). Under the command
of their Brigade-Major (Captain E. P. Combe, M.C.) the detachment
successfully held the enemy at bay from early morning until 6 p.m.,
when the eleven survivors withdrew under orders, having accomplished
their task.

There are many instances of the occupation of an area for an actual or
potential tactical purpose. Before the _Battle of Salamanca_ (July 22,
1812) a Spanish force had been detached by Wellington to cover a ford
of the River Tormes by occupying the castle of Alba de Tormes, but the
force was withdrawn without Wellington's knowledge, and Marmont's
defeated army retired unmolested over the ford to the fortress of
Valladolid. In the campaign of 181