Christianity is the largest religion in the world, with over 2 billion followers, but it has struggled to gain a foothold in certain parts of the world, particularly in Asia.

The religion originated in Judea and spread through the Levant, eventually reaching Antioch and spreading to Armenia, Georgia, Mesopotamia, Parthia, and India. Nestorian Christians are believed to have made their way from modern-day Iraq to China during the Tang Dynasty, with the earliest evidence of contact dating back to the 7th to 10th centuries.

The Christian mission in China was established by Alopen, a priest, in 635 AD and was initially welcomed by the Emperor despite resistance from local Buddhists and Daoists. Christianity surged in China during the Mongol period, as its leaders were more religiously tolerant, but it hit a stall under the Ming Dynasty.

Today, an estimated 20 million Christian adults live in China, comprising around 2% of the population. Taiwan and Japan also have Christian populations, with around 3% of Taiwanese and 1% of Japanese identifying as Christian. North Korea also has undercover Christians, thanks to evangelism by American Protestants in the 1800s.