Later, towards the mid 17th century, the harquebusier became the standard type of cavalry found throughout western Europe. The switch of the harquebusier from a mounted support role, reliant on firearms, to one of shock-capable close combat cavalry can be attributed to Gustavus Adolphus of Sweden in the 1620s and 1630s. Initially, this was from neccessity; Sweden was a relatively poor nation and could not afford to equip many expensive cuirassiers, therefore more lightly equipped cavalry had to be employed in a shock role. The success of Swedish cavalry in battle during the Thirty Years War led to other nations adopting their methods. Gustavus Adolphus also reduced the number of ranks in a cavalry formation from the previously usual six to ten, for pistol-based tactics, to three to suit hi