Russian grand duke (1864–1931); second and youngest son of Grand Duke Nicholas Nicolaievich the Elder and Duchess Alexandra of Oldenburg
Grand Duke Nicholas Nikolaevich of Russia
Knight of the Order of St. Alexander Nevsky
Brockhaus and Efron Encyclopedic Dictionary
Small Brockhaus and Efron Encyclopedic Dictionary
Imperial Monogram of Grand Duke Peter Nikolaevich of Russia.svg