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: In 1963, Haile Selassie presided over the establishment of the Organisation of African Unity, with the new organization establishing its headquarters in Addis Ababa.

In 1963, Haile Selassie led the creation of the Organisation of African Unity. The new organization set up its headquarters in Addis Ababa.