III. The priestly board of decemvirs (_sacris faciundis_) was an outcome of the claim of the _plebs_ to a share in the administration of the state religion. Five of the decemvirs were patricians, and five plebeians. They were first appointed in 367 B.C. instead of the patrician _duumviri_ who had hitherto performed these duties. The board was increased to fifteen in the last century of the Republic. Its chief function was the care of the Sibylline books, and the celebration of the games of Apollo (Livy x. 8) and the Secular Games (Tac. _Ann._ xi. 11).
IV. Decemvirs were also appointed from time to time to control the distribution of the public land (_agris dandis adsignandis_; see AGRARIAN LAWS).
BIBLIOGRAPHY.--B. G. Niebuhr, _History of Rome_ (Eng. trans.), ii. 309 et seq. (Cambridge, 1832); Th. Mommsen, _History of Rome_, bk. ii. c. 2, vol. i. pp. 361 et seq. (Eng. trans., new ed., 1894); _Römisches Staatsrecht_, ii. 605 et seq., 714 (Leipzig, 1887); A. H. J. Greenidge, _Legal Procedure of Cicero's Time_, p. 40 et seq., 263 (Oxford, 1901); J. Muirhead, _Private Law of Rome_, p. 73 et seq. (London, 1899); Pauly-Wissowa, _Realencyclopädie_, iv. 2256 et seq. (Kübler). (A. M. Cl.)
DECHEN, ERNST HEINRICH KARL VON (1800-1889), German geologist, was born in Berlin on the 25th of March 1800, and was educated in the university in that city. He subsequently studied mining in Bochum and Essen, and was in 1820 placed in the mining department of the Prussian state, serving on the staff until 1864, and becoming director in 1841 when he was stationed at Bonn. In early years he made journeys to study the mining systems of other countries, and with this object he visited England and Scotland in company with Karl von Oeynhausen (1797-1865). In the course of his work he paid special attention to the coal-formation of Westphalia and northern Europe generally, and he greatly furthered the progress made in mining and metallurgical works in Rhenish Prussia. He made numerous contributions to geological literature; notably the following:--_Geognostische Umrisse der Rheinländer zwischen Basel und Mainz mit besonderer Rücksicht auf das Vorkommen des Steinsalzes_ (with von Oeynhausen and La Roche), 2 vols. (Berlin, 1825); _Geognostische Führer in das Siebengebirge am Rhein_ (Bonn, 1861); _Die nutzbaren Mineralien und Gebirgsarten im deutschen Reiche_ (1873). But his main work was a geological map of Rhenish Prussia and Westphalia in 35 sheets on the scale of 1 : 80,000, issued with two volumes of explanatory text (1855-1882). He published also a small geological map of Germany (1869). He died at Bonn on the 15th of February 1889. (H. B. W.)