An Alliance created by Tsar Alexander I in the aftermath of the Napoleonic Wars. It came at a time when Alexander was deeply influenced by his Orthodox faith. It led to the British Foreign Secretary Castlereagh dubbing it a "piece of sublime mysticism and nonsense". He refused to allow Britain to join. The Tsar set it up as a counterbalance to the Quadruple Alliance of which Russia was also a member. Perhaps the best explanation of why comes from the Tsar:
"The Course formally adopted by the powers in their mutual relations had to be fundamentally changed and that it was urgent to replace it with an order of things based on the exalted truths of the eternal religion of our Saviour."
Metternich,
Chancellor of the
Habsburg Empire needed the Tsar's support to help maintain a conservative
balance of power that would favour the Habsburg Empire which had been seriously weakened as a result of the
Napeoleonic Wars. This was especially the case when considering the
Austria's gains which were
Lombardy and
Venetia (two
states) in an increasingly volatile Italian
Peninsula. Hence he backed the Holy Alliance.
But the Holy Alliance did not play the decisive the role the Tsar had initially desired. The Quadruple Alliance was far more significant and as the Tsar's deeply religious phase came to an end his interest in the Holy Alliance diminished. It can be seen as an attempt to show Russia's new acceptance into the European political fold. As an attempt to lead it failed but it is interesting in showing the inconstant character of Alexander I.