Interrex was literally a ruler "between kings", a short-term regent in the in the Roman Kingdom. Interreges, elected by the senate, were appointed under the republic for holding the comitia for the election of the consules, when the consules, through civil commotions or other causes, had been unable to do so in their year of office. Each held the office for only five days, as under the kings. The comitia were, as a general rule, not held by the first interrex, but more usually by the second or third.
- Interrex in Nova Roma