1912 CE
The International Opium Convention takes place

The International Opium Convention, signed at The Hague on January 23, 1912 during the First International Opium Conference, was the first international drug control treaty.  The convention was signed by representatives from China, France, Germany, Italy, Japan, the Netherlands, Persia (Iran), Portugal, Russia, Siam (Thailand), the UK and the British oversea territories (including British India). The convention took effect 3 years later in five countries. Seven years later (in 1919), it gained near-universal adherence when all the countries signing the Peace Treaties of Versailles also became party to the International Opium Convention. 

Source: The 1912 Hague International Opium Convention (n.d.). United NAtions Office on Drugs and Crime.