Aden, situated on the south coast of what is now Yemen, was a British colony since 1839. Commanding the southern entrance to the Red Sea, it was an important British air- and naval base on the route to India. It was also crucial for safeguarding access to Middle Eastern oil supplies. Aden did not get its own stamps until 1937. Todays stamp is from the first issue in 1937 with a denomination of ½ Anna.