This document outlines the timeline of key events related to the COVID-19 pandemic from December 2019 to January 2020. It describes how Chinese health officials began investigating cases of viral pneumonia in Wuhan in December. By late December, doctors were warned about the new disease but were later reprimanded by police for spreading rumors. In early January, a seafood market was shut down and a new coronavirus was identified. The genetic sequence was shared internationally on January 12th, allowing diagnostic tests to be developed. The first cases outside of China were reported shortly after.