the King, older than 18, or if there were none, the Belgian descendants of the main branch of the Royal house, were entitled to be senators by right by taking the oath of office. Senators by right over the age of 21 were in theory entitled to vote, but in practice they did not cast their vote. They were not taken into account for the required quorum for voting. Until Prince Philippe became King in July 2013, there were three senators by right (Prince Philippe, Princess Astrid and Prince Laurent). When the function of senators by right was abolished in 2014 as part of the sixth state reform, there were no senators by right, as King Philippe's children were all under the age of 18. Qualifications Article 69 of the Belgian Constitution sets forth four qualifications for senators: each senator must be at least 18 years old, must possess the Belgian nationality, must have the full enjoyment of civil and political rights, and must be resident in Belgium. Originally, the minimum age to be elected senator was 40; this was reduced to 21 in 1993 and eventually to 18 in 2014. A senator can only enter into office after having taken the constitutional oath, in either of the three official languages in Belgium: Dutch, French or German. They may also choose to take the oath in more than one language. The oath is as follows: "I swear to observe the Constitution". (, , ) Certain offices are incompatible with the office of senator. A member of the Senate may not be a member of the Chamber of Representatives at the same time and representatives must give up their seats in the Chamber of Representatives in order to join the Senate. Another important incompatibility is based on the separation of powers. A senator who is appointed as a minister ceases to sit in the Senate and is replaced for as long as he is a minister. However, if he resigns as a minister, he may return to the Senate, in accordance with Article 50 of the Belgian Constitution. A senator cannot also be a civil servant or a member of the judiciary at the same time. However, a civil servant who is elected to the Senate is entitled to political leave and doesn't have to resign as a civil servant. It is also not possible to be a member of the