Duke Alexander Petrovich of Oldenburg

Alexander's grandfather had married Grand Duchess Catherine Pavlovna, daughter of Paul I of Russia, and their descendants had been raised in Russia ever since and become completely "Russianized". Thus despite his German title, Duke Alexander, like his father before him, had grown up entirely in Russia, serving his military service for the czars. He was always considered a part of the Russian imperial family.

Like his two brothers, Alexander served in the Russian army. He held the position of Adjutant-General to Emperor Alexander III. He was also the commanding general of the Imperial Guard. Alexander served on the State Council

In 1889, Alexander resigned the office of commanding general of the Imperial Guard, because of the increasingly anti-German tone pervading into Russian politics, and also because he wanted to remove barriers that would bar his succession to the Grand Duchy of Oldenburg. Emperor Alexander refused his resignation, but gave the duke an eleven-month leave of absence.

Alexander was one of the richest princes in Russia in both landed and funded property; this was also partly due to the wealth of his wife, whose inherited wealth, as the granddaughter of Nicholas I of Russia, was said to be enormous. Alexander was also second-in-line to the throne of Oldenburg, as Frederick Augustus II, Grand Duke of Oldenburg had only one young son, Hereditary Grand Duke Nikolaus; were he to die before his father, Alexander would have become heir presumptive. Because of this wealth, it was expected that Alexander and his family would remain in Russia and give up their claim to the Grand Duchy of Oldenburg, were they to succeed to that particular territory.

Alexander was a doctor of medicine and undertook active management of the hospitals he helped in founding. At the outbreak of World War I in 1914, Emperor Nicholas II appointed Alexander to the post of supreme chief of the medical service of the military and naval forces. Though his selection as a royal duke was unusual to hold such a high medical-related position, there had been another precedent in another royal house, Prince Louis Ferdinand of Bavaria, who at that time was serving as surgeon general to the German army.

On 19 January 1868 at the Winter Palace, Alexander married Princess Eugenia Maximilianovna of Leuchtenberg, a daughter of Maximilian de Beauharnais, 3rd Duke of Leuchtenberg. Like his own family, Eugenia was also an offshoot of the Imperial family, as her mother was Grand Duchess Maria Nikolaevna, eldest daughter of Nicholas I of Russia. She was entitled to the rank Imperial Highness, and was born and raised in St. Petersburg.

The couple had one son, Peter. Eugenia had a long-standing friendship with Empress Maria Feodorovna, and the two helped arrange the marriage of Eugenia's son to Maria's daughter Grand Duchess Olga Alexandrovna.

Like his father before him, Alexander was well-educated and clever, and concentrated much of his time and energy to philanthropic works throughout Russia. He was president of several schools as well as the St. Petersburg-based Institute of Experimental Medicine. Alexander and Eugenia founded the Oldenburg Institute at Petrograd, where more than two thousands girls and boys received technical educations while being taught trades and given free lodging and food, all at the expense of the duke and duchess. Their extensive donations helped fund and found technical schools, hospitals, orphanages, as well as other philanthropic institutions all over Russia. As Alexander was a doctor, he was deeply involved in the management of these hospitals, taking charge of the sick and wounded on their departure from the field hospitals. In his position as chief of head of medical services for the Russian army and navy, Alexander invited hundreds of wounded French and British officers to stay free-of-charge in a sanatorium he founded in the Gagra. He also greatly improved the organization of wounded soldiers at the front.

While attending the opening of the Institute of Experimental Medicine as its main benefactor in January 1907, a prominent government official, General von Launitz, was assassinated before Alexander and Eugenia's eyes. The general was standing a few steps away from her husband, so that Eugenia, believing at first that Alexander had been the one killed, fell into a faint.

He and his wife's charitable exploits became so well known that a newspaper declared in 1914 that because they devoted their lives and the greater portion of their wealth to philanthropy, "there are probably no two who are so universally beloved as the Duke and Duchess Alexander of Oldenburg".