Complex sentence: In 1848 he published "Das Germanische Totenlager von Selzen", which was an important treatise on Germanic sepulchral mounds, and in 1851 he became head of the Romano-Germanic Central Museum in Mainz.
Split into simpler sentences: In 1848 he published "Das Germanische Totenlager von Selzen", an important treatise on Germanic sepulchral mounds. In 1851, he became head of the Romano-Germanic Central Museum in Mainz.