How did westerners justify their right to rule over other people?

Ineed with what i should write for my research paper. my topic is history of slavery. 1800 words. all i need is what to write in each paragraphs. like when the research paper has titles for each paragraph and it explains the tile in each paragraph. for example when did slaverh begin? why did it begin like an outline.

What factors allowed philip ii of macedonia to conquer the greek city-states?

What was the government purpose for creating “day schools”