Historically when we look at a civilization a prosperous one will always have a birth rate per capita, that is higher than the death rate,. therefore, any civilization that prospers with aboundant food, water, shelter and medicine will slowly increase untill it can no longer support a growing population. as a population grows it is in need of more basic neccessities to provide for the increase in number. to accomodate the growth of a civilization, they will need to produce more agriculture products and shelter. in order to split task evenly a government is established to provide law and order. eventually a population outgrows the amount required to provide the minimum amount of resources new jobs such as artistry, craftmanship and trade were created to increase production. population growth also results in more positions in government than just a head fiqure. we see the creation of governing law bodies, administration and a police force. the reason for the creation of a large government was to ensure fairness and the practicality of a single person in charge was found to be a weak government. some key role that they played included establishing and enforcing laws and creation of jobs to provide the civilization with necessary items. additionally a large population was also a safer population. before settlements people still lived nomadic lifestyles, where the threat of dying from circumstances like starvation and death by wild animals was very high. to increase safety they invented tools and machinery to improve the quality of life. tools and machinery went from being made from stone and bone to metal and intricate wood designs. this spurred populations to create improved structures, weapons, and monuments. some of the greatest structures in the world were built in the first civilizations and are still marvelous and magnificent to this date