The cursus honorum (career of honor) was the political career in Ancient Rome. The highest office was that of consul. There were strict rules and conditions attached to becoming a magistrate. But as the name implies, the cursus honorum was meant to be honorable. Thus the magistrate had to pay all his costs during his term in office. A magistrate was of course a member of the senate.
The hierarchy is ranked from the lowest office to the highest:
1. Qaestor, minimum age 31. He has to collect money (quaerere means to seek, to collect) Number: 2 in the beginning, 20 in the late republic
2. Aedilus, minimum age 37. Public games, distribution of food, police, fireman
3. Praetor, minimum age 41. Judge and decides which cases are worth to do
4. Consul, minimum age 45. President of the senate, general
5. Roman Dictator: 6 months and rather exceptional was given lot of power