ALTHUSIUS (Althus, Altusio), Johannes. - German Protestant jurist, b. in Ostfriesland or in the principality of Wittgenstein, c. 1556, d. at Emden in 1638. In 1590 he was appointed professor of law at Herborn; then in 1601 mayor of Emden, where, following his principles, he staunchly defended the rights of the city and the bourgeoisie against the count of Ostfriesland and the nobility.
Among his works the following deserve special mention: *Jurisprudentiae Romanae methodicae digestae atque exemplis sacris et profanis illustratae libri II* (Basel 1586–89, Herborn 1592–99, and elsewhere), placed on the Index by decrees of 20 March 1615 and 9 October 1618 for erroneous ideas regarding the principle of authority. According to Althusius, in fact, kings are merely magistrates: it is the people who possess authority and sovereignty, and they may change or even condemn to death the rulers they have elected. The State is nothing other than a federalist result of families, communes, and provinces; hence no absolute or totalitarian power should exist. Another of his works was also condemned (decree of 18 March 1620), a continuation of the first: *Dicaelogiae libri III totum et universius, quo utimur complectentes* (Herborn 1617 and elsewhere), in which he reiterates the same ideas: popular sovereignty, the mandate of the king or prince, revocable at the pleasure of the people. The same applies to a third work: *Politica methodica digestae* (Herborn 1603), though this was not specifically placed on the Index.