At what point of the history did kings stop fighting along with their armies during wars?

by VichySport
BritainOpPlsNerf

The Battle of Solferino is generally accepted as the last battle on the European continent in which both Armies were personally led by their Monarchs. Napoleon III led the French, Vittorio Emanuele the Sardinian contingent, while the Austrians were commanded by Franz Joseph. The battle occurred in the summer of 1859.