The Treaty of Paris (1951) establishing the European Coal and Steel Community established a right to free movement for workers in these industries and the Treaty of Rome (1957) provided a right for the free movement of workers within the European Economic Community. The Directive 2004 / 38 / EC on the right to move and reside freely assembles the different aspects of the right of movement in one document, replacing inter alia the directive 1968 / 360 / EEC. It also clarifies procedural issues, and it strengthens the rights of family members of European citizens using the freedom of movement. According to the official site of the European Parliament, the explanation of the freedom of workers goes as follows:

Based on this passage, when was free movement in the eu introduced? Let's think fast. Stream of consciousness:
To answer this question, we should know that: The Treaty of Paris (1951) establishing the European Coal and Steel Community established a right to free movement for workers in these industries and the Treaty of Rome (1957) provided a right for the free movement of workers within the European Economic Community. So the final answer is 1957.