 Complete the following phrase:  Berckheim led a cavalry brigade during the French invasion of Russia in 1812. The brigade was part of Jean-Pierre Doumercs 3rd Cuirassier Division in the III Cavalry Corps under Emmanuel de Grouchy. Like all three of Doumercs brigades, Berckheims brigade consisted of only one strong regiment, the 4th Cuirassiers, with 35 officers and 821 rank and file. The other two brigades were led by Samuel-François Lhéritier 7th Cuirassiers and Ignace Laurent Oullenbourg 14th Cuirassiers. At the 