Recently, one editor of the Changrui Education Company emailed the history department of Harvard University. He wants us to help him with the new world history text book of their company and hoped the edition can help more high school students to understand our world. As an ambitious and creative editor, he wants me to write about world history from 300 CE to 1500 CE by analyzing about three specific objects that have great impacts to people's life. Because I am a professor in the department and my graduate students are busy working on their papers, I was assigned with this job and hope my work can be helpful for the education of high school students.