The separation of powers theory in government is considered so important that Article III of the Virginia State Constitution concerns solely this underlying principle: namely, that the legislative, executive and judicial departments are to be separate and distinct. To emphasize this idea, the Constitution further states that neither department shall "exercise the powers properly belonging to either of the others nor may any person exercise the power of more than one of them at the same time." The Legislative Department--Since one of the chief functions of a government is to make laws, it is logical for Article IV of the Constitution to consist of a detailed description of the Legislative Department: its composition, membership, qualifications, powers and limitations. The State legislature or legislative branch is called the General Assembly. It is a bicameral legislature composed of an upper house, the Senate, and a lower house, the House of Delegates. This legislative body has been in continuous existence since 1619 and is believed to be the oldest one in the Anglo-Saxon world and the second oldest Parliament in the entire world. The Constitution requires that the Senate consist of not more than forty and not less than thirty-three members, elected quadrennially (once every four years). There are forty members in the present State Senate, and their term of office is four years. They are elected to office by the qualified voters of the State Senatorial Districts on the first Tuesday following the first Monday in November of every other odd-numbered year in which the Governor is not elected. Therefore, they are elected during the mid-term of the Governor. The State Constitution requires that the House of Delegates consist of not more than one hundred and not less than ninety members. In the present House of Delegates, there are one hundred members, and their term of office is two years. Members of the House are elected to office by the qualified voters of the State House districts on the Tuesday following the first Monday in November of every odd-numbered year. Both the Senatorial and House of Delegates Districts are set up by the General Assembly in that a special commission is appointed by the governor to do the districting: this commission membership must be approved by the General Assembly. The Constitution requires that reapportionment or redistricting take place every ten years to offset population changes. The last reapportionment was made in 1952; therefore, the next reapportionment or redistricting is due in 1962. There are now thirty-six State Senatorial Districts, thirty-three of which are entitled to one Senator each and seventy-six House of Delegates' districts, sixty-two of which are entitled to one Delegate each.