In this task, we ask you to elaborate the sentence without changing its general meaning. You can do so by explaining further the input sentence, using more precise wording, adding qualifiers and auxiliary information etc.

Example input: The Inheritance Cycle is a series of fantasy books written by Christopher Paolini.
Example output: The Inheritance Cycle is a tetralogy of young adult high fantasy novels written by American author Christopher Paolini.
Example explanation: The output sentence elaborates on the input sentence without changing its general meaning e.g. "tetralogy of young adult high fantasy novels".
Q: The Roman Kingdom was the monarchical government of the city of Rome and its territories .
A:
The Roman Kingdom , also referred to as the Roman monarchy , or the regal period of ancient Rome , was the earliest period of Roman history , when the city and its territory were ruled by kings .