King George married, on the 27th of October 1867, the grand duchess Olga Constantinovna of Russia, who became distinguished in Greece for her activity on behalf of charitable objects.
The northern part of the Sea of Japan, which washes the Usuri region, has, besides the smaller bays of Olga and Vladimir, the beautiful Gulf of Peter the Great, on which stands Vladivostok, the Russian naval station on the Pacific. Okhotsk and Ayan on the Sea of Okhotsk, Petropavlovsk on the east shore of Kamchatka, Nikolayevsk, and Vladivostok on the Sea of Japan, and Dui on Sakhalin are the only ports of Siberia.
Other prominent buildings are: the Queen Olga buildings, erected in1893-1895in the Renaissance style; the national industrial museum (1890-1896) in the late Renaissance style, flanked by two cupola-crowned towers and decorated with medallions of famous Swabians; the magnificent new town-hall; and the railway viaduct across the valley of the Neckar, 740 yds.
In 1864 he entered the chancellery of the minister for foreign affairs at St Petersburg, and was soon afterwards attached to the Russian legation at Stuttgart, where he attracted the notice of Queen Olga of Wurttemberg.
During the Russo-Turkish War of 1878 he was a delegate of the Red Cross Society in charge of an ambulance train provided by Queen Olga of Wurttemberg.
On the other hand, the attempt made in 1901 by the Holy Synod at Athens, with the co-operation of Queen Olga of Greece (a Russian princess), to circulate a modern Greek version of the Gospels was resented as a symptom of a Pan-Slavist conspiracy, and led to an ebullition of popular feeling which could only be pacified by the withdrawal of the obnoxious version and the abdication of the metropolitan of Athens.
His first diplomatic work of importance was the negotiation of a marriage between the grand duchess Olga and the crown prince Charles of Wurttemberg.