map correction for data on Thrace The map territorial gains until 1947 shows Western Thrace as coming under Greek rule in 1923 whereas other sources indicate that the date should be 1920 Both Eastern and Western Thrace were acquired by Greece in 1919 1920 and then Eastern Thrace reverted to Turkey in 1923 correctly shown on map per the Encyclopaedia Britannica entry for Thrace and the Wikipedia article on Thrace Needs