Justus Lipsius (Joose Lips or Josse Lips) (18 October 1547 – 23 March 1606) was a Southern - Netherlandish (Belgian) philologist and humanist. Lipsius wrote a series of works designed to revive ancient Stoicism in a form that would be compatible with Christianity. The most famous of these is De Constantia (On Constancy). His form of Stoicism influenced a number of contemporary thinkers, creating the intellectual movement of Neostoicism. He taught at the universities in Jena, Leiden and Leuven.

His ideas about the ideal citizen — a man that acts according to reason, is answerable to himself, is in control of his emotions, and is ready to fight — found wide acceptance in the turbulent times of the Reformation. This Lipsian view, translated to politics, entails rationalisation of the state and its apparatus of government, autocratic rule by the prince, discipline dispensed to subjects, and strong military defence. These principles lie at the foundation of the early modern state.

Lipsius was born in Overijse, Brabant. His parents sent him early to the Jesuit college in Cologne, but they feared that he might become a member of the Society of Jesus, so when he was sixteen they removed him to the University of Louvain.

The publication of his Variarum Lectionum Libri Tres (1567), which he dedicated to Cardinal Granvelle, earned him an appointment as a Latin secretary, and a visit to Rome in the retinue of the cardinal. Here Lipsius remained for two years, devoting his spare time to the study of the Latin classics, collecting inscriptions and examining manuscripts in the Vatican. After he returned from Rome, he published a second volume of miscellaneous criticism (Antiquarum Lectionum Libri Quinque, 1575); compared with the Variae Lectiones of eight years earlier, it shows that he had advanced from the notion of purely conjectural emendation to that of emending by collation.

In 1570 he travelled through Burgundy, Germany, Austria, and Bohemia, where the University of Jena engaged him as a teacher for more than a year, a position which implied conformity to the Lutheran Church. On his way back to Leuven, he stopped some time at Cologne, where he must have comported himself as a Catholic.

He then returned to Leuven, but the Eighty Years' War soon drove him to take refuge via Antwerp to the Northern Netherlands, where, in 1579, the newly founded University of Leiden appointed him professor of history.

At Leiden, where he must have passed as a Calvinist, Lipsius remained eleven years, the period of his greatest productivity. It was now that he prepared his Seneca, and perfected, in successive editions, his Tacitus, and brought out a series of other works. Some were pure scholarship, some were collections from classical authors, and others were of general interest. One of this latter class was a treatise on politics (Politicorum Libri Sex, 1589), in which he showed that, though a public teacher in a country which professed toleration, he had not departed from the state maxims of Alva and Philip II. He wrote that a government should recognize only one religion, and extirpate dissent by fire and sword. This avowal exposed him to attacks, but the prudent authorities of Leiden saved him, by prevailing upon him to publish a declaration that his expression Ure, seca ("Burn and carve") was a metaphor for a vigorous treatment.

In the spring of 1590, leaving Leiden under pretext of taking the waters at Spa, he went to Mainz, where he reconciled with the Roman Catholic Church. This event deeply interested the Catholic world, and invitations from the courts and universities of Italy, Austria and Spain poured in on Lipsius. But he preferred to remain in his own country, and he finally settled at Leuven, as professor of Latin in the Collegium Buslidianum.

He was not expected to teach, and appointments as privy councillor and historiographer to Spain's King Philip II eked out his trifling stipend. He continued to publish dissertations as before, the chief being his De militia romana (1595) and his Lovanium (1605), intended as an introduction to a general history of Brabant.

Lipsius died at Leuven. For years, a street off the Wetstraat in the Etterbeek quarter of Brussels, commemorated his name. In the 1990s, construction for the new home of the Council of the European Union built over the road, but the honorific remains: the EU headquarters now resides in the Justus Lipsius building.

The name of Justus Lipsius drew new public attention in 1995 when it was chosen for the new Brussels headquarters building of the Council of the European Union. He was also recently selected to appear on the 10 euro Justus Lipsius Silver commemorative Coin, minted by Belgium in 2006. The reverse side of the coin shows his portrait together with the years of his life (1547 - 1606).