The Setting

Mythological novel ?
Wu Cheng'en's  Journey to the west  is essentially a mythological novel, which means it is not incorporated within the original mythical stories that explain how the world is created and etc. However, a mythological novel is a story based on those original mythical stories. Throughout the years, readers and writers tried to link different mythological stories and form a congregated storyline, but there's still a lot of disagreements with settings and character relationships. Although there isn't a 'perfect storyline' that everybody agreed to, these efforts of merging mythological novels together have given birth to exciting conspiracy theories and other innovative stories, which to some degree, influenced some of the modern-day "Wuxia" stories.

The History
Although  Journey to the west is considered a mythological novel, it is inspired by real historical events that took place 1400 years ago during the Tang Dynasty. For example, Xuanzang, the prototype of Tang Seng, was one of the greatest travelers, Buddhist scholar, and translator in China's history. Xuan Zang's pilgrimage from Chang'an (Modern day Xi'an) to the kingdom of Dagamirah took around 19 years and went through 138 countries (the number could be incorrect since there are controversies on how many countries Xuan Zang had actually gone through). Xuan Zang traveled around 25000 km in total, bringing hundreds of Buddhist scriptures back to China; after that, he spends over twenty years translating the scriptures into Chinese. Xuan Zang also wrote Buddhist Records of the Western World in which he described his westward pilgrimage, the different cultures along the way and things that he has experienced.

Inspired by Xuan Zang's story, Wu Chengen then writes the Journey to the west; however, he is not the only writer inspired by the westward pilgrimage. There were several versions of  Journey to the west  during and even before the Ming dynasty when the  Journey to the west  is believed to be written. More importantly, the original copies of the most famous version of  Journey to the west  didn't have the author's name written on it, complicating the problem even more. How much of Wu Chengen's  Journey to the west  original? Is Wu Chengen really the actual author of the book? We don't know the answers to these questions for sure, but most experts agreed that Wu Chengen is the real author.