Ius emigrandi of the Religious Peace of Augsburg (1555)
The ius reformandi (literally right to reform) stipulated that the confession of the territorial lord determined the confession of his subjects. The ius emigrandi (right to emigrate) of the Religious Peace of Augsburg promised one initial form of immigration freedom for subjects: it allowed individuals with different beliefs (after the payment of a departure tax) to immigrate to a territory whose territorial lord shared their confession. Serfs were still essentially excluded from this right; whether they were allowed to emigrate remained at the discretion of their lords. Not until the Peace of Westphalia (1648) were serfs also granted the right to emigrate. Admittedly, the principle cuius regio, eius religio (whose land, his religion) left the lords only two choices when it came to confession: Roman Catholic or Lutheran.
§ 24. [Right to Emigrate of those who Change Religion] It may happen that Our subjects or those of the electors, princes, and other estates, either of the old faith or the Confession of Augsburg, wish to leave Our lands or those of the electors, princes, and estates of the Holy Roman Empire, together with their wives and children, and settle elsewhere. They shall be permitted and allowed to do so, to sell their goods and possessions, after having paid a reasonable sum for freedom from servile obligations and for taxes in arrears, such as has everywhere been customary for ages. Their honorary posts and their obligations, however, shall be unrecompensed. Their lords, however, shall not be deprived thereby of their customary right to demand recompense for granting freedom from servility.
Source: Select Documents Illustrating Medieval and Modern History. Translated by Emil Reich. London: P.S. King & Son, 1905, pp. 226-32 [edits and additions by Thomas A. Brady, Jr.].