Wallenstein
2 of the 7 encyclopedias on this shelf carry an entry for Wallenstein. Both are reproduced below, so you can see where they agree and where they differ.
Collier's New Encyclopedia (1921)
ALBRECHT WEN- ZEL EUSEBIUS, COUNT VON (val' len-stine), the great general of the Imperialists, in the Thirty Years' War; born in 1583, of an ancient and wealthy family of Bohemia. In his youth he repaired to Italy, where he studied philosophy, astronomy, and the sciences then in vogue, and would have become an adept in the abstruse doctrines then so generally believed in, had not the condition of his country called him from the study of the occult sciences to the practice of war. As a soldier and leader he gained honor and distinction on his first field by defeating the Turks, who had penetrated into Hungary. From this time he devoted himself to the service of his country, and in a few years rose to be regarded as the most popular and consummate general in Europe; his vast wealth, immense estates, and extraordinary popularity giving him a power less than sovereign. and influence hardly He became in a few years the mainstay and support of the Imperial cause, and, both alone and in conjunction with Tilly, obtained several victories, and more than once raised the empire fro from the verge of ruin by his counsel and skill as a commander. For these services he received the dukedom of Mecklenburg, and immense tracts of land both in Bohemia and Hungary. His power and his influence, however, procured for him many enemies, to whom his sovereign, forgetful of the services he had rendered, lent so willing an ear that Wallenstein, indignant at the coldness of the emperor, threw up his commission and retired to the privacy of his paternal estates. Hardly had Wallenstein quitted the court of his ungrateful master when the "Lion of the North," as he was called- Gustavus Adolphus of Sweden-invaded the empire ire with his Protestant army, and carried such defeat and ruin into the heart of the Imperial dominions, that the Emperor Ferdinand, seeing his generals slain, his armies routed, and the • haughty foe advancing on his capital, was compelled to implore Wallensteinthe man he had so deeply injured to return, and not only save the empire from ruin, but his sovereign from humiliation. Having obtained his own terms from the weak and ungrateful Ferdinand, Wallenstein raised his banner, and so much was he beloved by the soldiery that in less than seven days he had armed and equipped 50,000 men at his own cost, and advancing against the successful enemy, drove Gustavus out of Bavaria, and following him into Saxony, forced him at Lützen to hazard a pitched battle, in which, though the Imperialists were defeated, the death of Gustavus, who fell in the moment of victory, was considered an ample equivalent. The death of the Swedish king made the rest of the war easy, and by Wallenstein's vigilance the empire was again saved. Ferdinand, once more firmly seated on his throne, again became envious of the man to whom he owed both life and crown, and, taking offense at the devotion of Wallenstein's officers, accused EDMUND WALLER their chief of treason, and issued an order to take him dead or alive. On this Wallenstein fled with a party of friends to the castle of Eger, where its commander treacherously murdered him and all his devoted friends, in 1634.
Aiton's Encyclopedia (1910)
wol'en-stin (1583-1634), a German soldier. He was a native of Bohemia, the heir of a Protestant family of high rank. He studied with the Jesuits and was converted to Catholicism. He attended the universities of Altdorf, Bologna, and Padua. In a war with Venice he was made a count and given the rank of colonel in the Austrian army. At the outbreak of the Thirty Years' War, he was first and foremost in putting down the revolt of the Protestant Bohemians. As a reward he was permitted to enrich himself enormously with the confiscated estates of the Bohemian nobility. As the war progressed he became field-marshal of the empire and cooperated with the renowned Tilly. He overran Silesia, drove the Danes out of Germany, and fought the battle of Lutzen in which Gustavus Adolphus fell. His soldiers are said to have plundered or destroyed $400,000,000 worth of property. In the meantime, so signal had been his success, he had incurred the jealousy of the Austrian nobility and had been deprived of command temporarily. The facts appear to be that his own party, the Catholics, feared his wealth, his capacity for affairs, military skill, energy, and ambition. He was suspected of designs to make himself emperor. It was suspected that he aimed to make himself master of Europe, an early Napoleon Bonaparte as it were. He was known to be in correspondence with the Protestant forces, some aver to betray them; others claim to betray the Catholic cause. At all events the emperor was induced to make proclamation removing him from command and forbidding all forces to obey his orders. Wallenstein retired haughtily to the fortress of Eger, Bohemia. Here he was assassinated by a quartette of scoundrels, two Scotchmen and two Irishmen, on the night of February 25, 1634. The emperor rewarded them publicly. Wallenstein's fidelity or otherwise to the Catholic cause is one of the fiercely disputed questions of history. Schiller made him the subject of a series of three noted plays, Wallenstein's Camp, The Piccolomini, and Wallenstein's Death.