Why did people of sumer practiced the worship of many gods?

Answer 1

There are so many greek gods and goddesses because the Greeks believed there was a god or goddess for most specific things; gods and goddesses for war, hunting, childbirth, love, arts & crafts, household, etc.

Answer 2

Some civilizations, like Egypt, were composed of many local communities who often had a chief local god or gods. When communities got larger and combined into larger nations, they also combined their religions. This was also true of ancient Greece.

Sometimes each force of nature has a separate god, like the sun, wind, rain, etc. because these forces have different "personalities".

Answer 3

polythheism