Leuchtenberg, a mediatized principality of Bavaria, in the district of the Upper Palatinate; area, about 80 sq. m.; pop. about 6,500. Capital, Pfreimdt (pop. 1,600). It took its name from a lofty castle still existing in the village of the same name, which was the cradle of landgraves whose male line became extinct in 1646 with the death of Adam Maximilian. His brother-in-law, Duke Albert, succeeded to the domain in 1647, but relinquished it in favor of his brother the elector Maximilian of Bavaria, who ceded it to his second son Maximilian Philip. After various changes it was reunited with Bavaria in 1714. In 1817 King Maximilian Joseph ceded it for 5,000,000 francs, together with a portion of the principality of Eichstadt, to his son-in-law Eugene de Beauharnais, conferring upon him the titles of duke of Leuchtenberg and prince of Eichstadt, with the right of succession to the sovereignty in the event of the extinction of the male line of Bavarian kings. (See Beauharnais, Eugene de.) - The successor of Eugene, his elder son Charles Auguste Eugene Napoleon (1810-'35), dying two months after his marriage with Queen Maria of Portugal, Leuchtenberg reverted to his brother Max Eugene Joseph Napoleon (born in Munich, Oct. 2, 1817, died in St. Petersburg, Nov. 1, 1852). He married in 1839 the grand duchess Maria, daughter of the emperor Nicholas of Russia. He received the title of imperial highness, and his four sons that of Princes Roma-novski. The eldest of the latter, Duke Nicholas Maximilian (born in St. Petersburg, Aug. 4, 1843), is the present head of the house of Leuchtenberg and the owner of the Russian domain of Tambov, which his family acquired in 1845 after the sale of their property in the Papal States for 20,000,000 francs to the Roman see.

The mother of Duke Nicholas, the grand duchess Maria, contracted a second marriage with the Russian count Grigori Strogo-noff, Nov. 16, 1856. The duke is a major general on the staff of the emperor Alexander II., and was in attendance on him when attempts upon Alexander's life were made in St. Petersburg in 1866, and in Paris in 1867. In 1873 he was aide-de-camp to Gen. Kaufmann in Khiva.