It was on this day that the first ever stamped letter was posted, and we are asking you to mark the anniversary by sending a letter or postcard to a political prisoner in Burma.
Last week thousands of people around the world wore blue shirts in support of political prisoners in Burma. Almost 200 remain in jail. The day of action was reported widely in media in Burma, increasing pressure on the government to release them. Thank you to all of you who took part.
We need to keep up the momentum, and also let political prisoners know that they haven't been forgotten. We know from former political prisoners that it really means a lot when they receive a postcard or letter.
Conditions in prison are harsh, food is terrible, many political prisoners get ill, and they are worried about how their families are surviving. They committed no crime, they just tried to help their community or their country, or happen to come from an ethnic group the military don't like.
A letter or postcard can mean more than you can imagine. You might be worried about what to say, but even one or two sentences on a postcard: 'greetings from XX country, we are campaigning for your release', is enough.
If you live outside Burma, posting an international letter can be a pain, queuing at a post office, but for that effort you'll be doing something very special for someone. In many countries now you can even buy and print stamps online.
So please take a few minutes to write to a political prisoner. A letter, an old postcard, whatever you have handy.