Definition: Rewrite each original sentence in order to make it easier to understand by non-native speakers of English. You can do so by replacing complex words with simpler synonyms (i.e. paraphrasing), deleting unimportant information (i.e. compression), and/or splitting a long complex sentence into several simpler ones. The final simplified sentences need to be grammatical, fluent, and retain the main ideas of their original counterparts without altering their meanings.
Input: The early Spartans believed helmets were unnecessary and boxing prepared them for the inevitable blows to the head they would receive in battle.

The early Spartans believed that they did not need helmets. They thought that boxing prepared them to get hit in the head during battle.