The Curiate Assembly ("comitia curiata") was the principal assembly that evolved in shape and form over the course of the Roman Kingdom up until the Comitia Centuriata organized by Servius Tullius. During these first decades, the people of Rome were organized into thirty units called "Curiae". The Curiae were ethnic in nature, and thus were organized on the basis of the early Roman family, or, more specifically, on the basis of the thirty original patrician (aristocratic) clans. The Curiae formed an assembly for legislative, electoral, and judicial purposes. The Curiate Assembly passed laws, elected Consuls (the only elected magistrates at the time), and tried judicial cases. Consuls always presided over the assembly. While plebeians (commoners) could participate in this assembly, only the patricians (the Roman aristocrats) could vote.