what was the function of the Roman cavalry?

[Aryaman2]

My first post on this forum. Very interesting.

My tuppence take on cavalry v. infantry is this; horses will not go too close to a solid object - especially one that they don't like due to colour, shape, noise, whatever goes on in a horses brain etc. Trained warhorses may get closer, but it seems that instances of cavalry breaking *formed* infantry presenting pila/spears/pikes/ fixed bayonets are extremely rare - the well-documented examples from the Napoleonic Wars only seem to occur when horses crash into squares when killed/badly wounded i.e. the pursuit after Talavera (or is it Salamanca?) At Albuera the infantry were surprised from the flank during heavy rain, and by lancers, who could out-reach the infantry in any case, and in the case of the famous portrait of French cavalry flowing around British squares at Waterloo, apparently the cavalry are about 50m closer than they actually got to the squares!

In the C17th it is well attested that cavalry were repulsed by formed infantry, especially pikemen (i.e. LTB at Newbury and Price Ruperts Bluecoats at Naseby) and were only broken when their formation was broken up or they began to waver. The old-fashion caracole was intended to whittle the infantry down prior to a charge, but a charge against fresh troops relied on psychological effects.

Those are characteristic examples of British bibliography, remember that Napoleonic Wars were fought in many other places besides the Peninsular War and many other wars were fought in the 17th century besides the English Civil War. I point 2 famous examples of cavalry crashing into and overruning steady infantry, Eylau and Wimpfen