On 28 July 1516 he was born in Duesseldorf, son of Johann III, Duke
        of Cleves. In 1539 he succeeded his father and became Duke of Cleves, 
        Juelich and Berg. On 13 July 1541 he married Jeanne d'Albret, heiress 
        of the kingdom of Navarre. In 1543 in the Treaty of Venlo, Wilhelm III 
        was compelled to concede to the victorious Emperor Charles V that he 
        would not allow the introduction of the Reformation in his lands. 
            Both the expenses of the war and the religious concession were 
        unpopular with Wilhelm's estates, which took up a position of steady 
        opposition to any policies that smacked of ducal autocracy or 
        "despotism". Many towns and noblemen of the lower Rhine had already, 
        by 1540 or 1550, gone over to the Protestant Reform and the Protestant 
        movement accelerated only after that. 
            In 1546 he was divorced from his wife and, on 18 July 1546 in 
        Regensburg, married Archduchess Maria of Austria and they became the 
        parents of five daughters and two sons. 
            For his part Duke Wilhelm showed a remarkable moderation in 
        religious matters, inspired in part by his Erasmian education at the 
        hands of Conrad von Heresbach. Despite his pledge to Charles V, he 
        continued to support outright Protestants at his court, such as his 
        personal physician, Johann Weyer, or his court preacher, Gerhard Vels, 
        three of his daughters were raised Protestant and married Protestant 
        princes. His apparent stance of evangelical humanism, or as some 
        suspected, covert Protestantism, also found expression in his 
        steadfast support of taking the eucharist under both species (both 
        bread and wine) and his opposition to witchcraft trials. Apparently 
        following Weyer's advice, he did not approve or confirm a single 
        witch's execution, although evidently he did reintroduce the 
        controversial "water test" for witchcraft in 1581, a procedure in 
        which those accused of withcraft were dunked in a pond to test their 
        claims of innocence. 
             Unfortunately, Wilhelm the Rich fell victim to a series of eleven 
        strokes in his fiftieth year during and after the imperial diet at 
        Augsburg in 1566 and, as a result, lost control of his government from 
        time to time over the next twenty-five years. Though he had not given 
        up his government, he was increasingly under the influence of fervent 
        Catholic councillors, especially, perhaps, Wilhelm von Waldenburg. 
           Weakness in the old duke was unfortunately a growing fact of life. 
        It is not fair to claim that he was mad or totally incapacitated from 
        1566 onwards, but he was indeed paralyzed on his left side and 
        suffered a permanent slurring of his speech. His motions and gestures 
        evidently became more rigid and lacking in spontaneity. Although he 
        still undertook long trips in the early 1570s, such as the wedding 
        journey to K”nigsberg in 1573, by the late 1570s his travels were 
        over. 
              During the 1580s, saddened by the premature death of his elder 
        son, Karl Friedrich, in 1575 at the age of eighteen, Wilhelm fell more 
        and more often into paroxysms of unconsciousness or perhaps mental 
        illness. Right up to his death in January 1592, Wilhelm remained a 
        figure to contend with. Although his councillors took over almost all 
        of the daily business at court, yet they did not succeed in setting up 
        a regency or "curatel" for him; and in his last years they had to 
        watch, helplessly, as Wilhelm fell out with his only surviving son, 
        Johann Wilhelm. 

Source: Leo van de Pas