The 1st Guard Cavalry Division had four regiment

Regiment

A regiment is a major tactical military unit, composed of variable numbers of batteries, squadrons or battalions, commanded by a colonel or lieutenant colonel...

s: His Majesty's Cuirassier

Cuirassier

Cuirassiers were mounted cavalry soldiers equipped with armour and firearms, first appearing in late 15th-century Europe. They were the successors of the medieval armoured knights...

 Guards Regiment (Leib-Gvardii Kirasirskii Ego Velichestva Polk), Her Majesty's Cuirassier Guards Regiment (Leib-Gvardii Kirasirskii Eia Velichestva Polk), His Majesty's Cossack

Cossack

Cossacks are a group of predominantly East Slavic people who originally were members of democratic, semi-military communities in what is today Ukraine and Southern Russia inhabiting sparsely populated areas and islands in the lower Dnieper and Don basins and who played an important role in the...

 Guards Regiment (Leib-Gvardii Kazachii Ego Velichestva Polk), and the Ataman Cossack Guards Regiment of H. I. H. the Tsesarevich

Tsesarevich

Tsesarevich was the title of the heir apparent or presumptive in the Russian Empire. It either preceded or replaced the given name and patronymic.-Usage:...

(Leib-Gvardii Atamanskii Ego Imperatorskago Vysochestva Naslednika TSesarevicha Polk).