Citizens were organized on the basis of centuries and tribes, which would each gather into their own assemblies. The Comitia Centuriata ("Centuriate Assembly") was the assembly of the centuries (i.e. soldiers). The president of the Comitia Centuriata was usually a consul. The centuries would vote, one at a time, until a measure received support from a majority of the centuries. The Comitia Centuriata would elect magistrates who had imperium powers (consuls and praetors). It also elected censors. Only the Comitia Centuriata could declare war, and ratify the results of a census. It also served as the highest court of appeal in certain judicial cases.
Which elected official had imperium powers?
magistrates