Complex sentence: He was elected to the U.S. House of Representatives, and then to the U. S. Senate, Jackson was in 1801 appointed colonel in the Tennessee militia, which became his political as well as military base.
Split into simpler sentences: He was elected to the U.S. House of Representatives, and then to the U. S. Senate. In 1801, Jackson was appointed colonel in the Tennessee militia, which became his political as well as military base.