774: EUGENIUS EULER princes, and particularly by the king of Ara- gon and the duke of Milan. The members of the council therefore proceeded to act at first independently of the pope, and soon after against his authority and person. (See BASEL, COUNCIL OF.) The efforts of Sigismund, who was crowned in Rome in August, 1433, brought about a momentary peace between pope and council ; but the revolutionary measures of the latter compelled the pope to dissolve it in June, 1437. An oecumenical council was opened in Ferrara Jan. 10, 1438 ; on Jan. 27 the pope arrived to preside in person, and early in Feb- ruary the Greek emperor, John Palseologus, and a large number of Greek bishops, arrived in Ferrara, after having been magnificently en- tertained in Venice. The plague soon break- ing out, the pontiff transferred the council to Florence, where on July 6, 1439, was published the decree of union of the Greek and Latin churches. (See FLORENCE, COUNCIL or.) The Armenians, Jacobites, and other eastern com- munions sent in their adhesion subsequently, either before the end of this council or during that held in Rome in 1444. Meanwhile the refractory prelates of Basel had elected an antipope in the person of Amadeus of Savoy. In 1435 Joanna II. of Naples bequeathed her crown to Ren6 of Anjou; but the king of Aragon claimed it as his rightful inheritance, and supported his claim by a powerful arma- ment. The pope, who was the acknowledged suzerain of Naples, rejected both pretenders, and a calamitous war followed between him and Alfonso. It ended by the pope's granting the investiture of the kingdom to Alfonso, and by the latter's aiding the pope to repel the attacks of his own domestic enemies. The pope was thus enabled to reenter Rome Oct. 28, 1443, after nine years' absence ; and he im- mediately convened a new council to meet in St. John Lateran in 1444. A new storm had been threatening Eugenius from the side of Germany. The bishops of Cologne and Treves had been excommunicated and deposed by him for their adherence to the antipope. As they enjoyed the rank of prince-electors of the em- pire, the whole electoral body took up their quarrel, which was also espoused by the em- peror and all the German princes. They had taken at first a position of neutrality between Eugenius and the antipope ; but the persistent refusal of the former to revoke his sentence of deposition brought on a threat of recogni- zing Felix V. as the lawful pope. At length, through the good offices of JEneas Sylvius Pic- colomini, afterward pope as Pius IL, the diffi- culty was settled, and all Germany declared formally against the antipope (1447). One of the great anxieties of Eugenius had been the steady progress westward of the Mohammedan power. The letters of the pontiff and the earnest exhortations of his legate Cesarini had induced Ladislas, the young king of Poland and Hungary, to take up arms against the Turks in 1440. The victories of Hunyady at length forced them to conclude a peace for ten years, and the treaty had been solemnly sworn to on the Gospel and Koran. The pope, however, re- fused to accept the peace, on the pretext that it had been concluded without his knowledge ; a new war was begun, which ended on the field of Varna (1444), where Ladislas perished with 10,000 of his followers. Eugenius declared this disaster to be the bitterest affliction in his troublous life. In 1447, simultaneously with the settlement of the German difficulty, a plan was submitted to the pope by the French king for ending the schism in the church. This was accepted, and caused unbounded joy, in the midst of which Eugenius sickened and died. He has been reproached with his monkish austerity of life, with rashness and inconstan- cy in many tilings, and inflexible obstinacy in others. Those most opposed to him allowed him, nevertheless, the praise of an unblemished life. He was, without being learned himself, a most generous patron of learning. EULER, Leonhard, a Swiss mathematician, born in Basel, April 15, 1707, died in St. Pe- tersburg, Sept. 7, 1783. He was intended for the church, and entered the university of Ba- sel ; but the influence of the Bernoullis divert- ed his attention to philosophical pursuits. At the age of 19 he graduated, after having already attracted the notice of the French academy of sciences by a memoir upon some points of na- val architecture. In the following year he went to St. Petersburg, where after several dis- appointments Daniel Bernoulli obtained for him the professorship of natural philosophy ; and in 1733 he became professor of mathematics. His publications on the nature and propagation of sound, curves, the integral calculus, the move- ment of celestial bodies, &c., had gained him wide reputation; and in 1741, at the invitation of Frederick the Great, he left St. Petersburg for Berlin, where he remained 25 years. Du- ring this time he continued to hold his Russian appointments, and even drew a portion of their salary, receiving at the same time from all parts of Europe the most flattering marks of respect. When the dominions of Frederick were in- vaded by a Russian army in 1760, and a farm belonging to Euler was laid waste, the empress Elizabeth immediately reimbursed his losses. These generous acts, among other motives, in- duced him to accept an invitation from the em- press Catharine II. to return to St. Petersburg in 1766. He had during some years previously suffered from weakness of the eyes ; and soon after returning to Russia he became so nearly blind as to be able only to distinguish very large chalk marks on a blackboard. The affec- tion was the consequence of fever brought on by a calculation, for which his fellow acade- micians demanded four months, but which Eu- ler completed in three days. He continued al- most blind during the remainder of his life ; but by constant exercise he acquired a power of recollection of mathematical formulas and figures almost incredible. Some of his most
