Complex sentence: From the rise of José Tadeo Monagas to the Presidency in 1847, Castro began to be promoted in the military system: in 1849 he was promoted to Commander (now Major).
Split into simpler sentences: From the rise of José Tadeo Monagas to the Presidency in 1847, Castro began to be promoted in the military system. In 1849 he was promoted to Commander (now Major).