of the king's supporters, who completed The history of King Richard the Third in 1619. The authoritative Buck text was published only in 1979, though a corrupted version was published by Buck's great-nephew in 1646.</ref> Buck attacked the "improbable imputations and strange and spiteful scandals" related by Tudor writers, including Richard's alleged deformities and murders. He located lost archival material, including the Titulus Regius, but also claimed to have seen a letter written by Elizabeth of York, according to which Elizabeth sought to marry the king. Elizabeth's supposed letter was never produced. Documents which later emerged from the Portuguese royal archives show that after Queen Anne's death, Richard's ambassadors were sent on a formal errand to negotiate a double marriage between Richard and the Portuguese king's sister Joanna, of Lancastrian descent, and between Elizabeth of York and Joanna's cousin Manuel, Duke of Viseu (later King of Portugal). Significant among Richard's defenders was Horace Walpole. In Historic Doubts on the Life and Reign of King Richard the Third (1768), Walpole disputed all the alleged murders and argued that Richard may have acted in good faith. He also argued that any physical abnormality was probably no more than a minor distortion of the shoulders. However, he retracted his views in 1793 after the Terror, stating he now believed that Richard could have committed the crimes he was charged with, although Pollard observes that this retraction is frequently overlooked by later admirers of Richard. Other defenders of Richard include the noted explorer Clements Markham, whose Richard III: His Life and Character (1906) replied to the work of Gairdner. He argued that Henry VII killed the princes and that the bulk of evidence against Richard was nothing more than Tudor propaganda. An intermediate view was provided by Alfred Legge in The Unpopular King (1885). Legge argued that Richard's "greatness of soul" was eventually "warped and dwarfed" by the ingratitude of others. Some 20th-century historians have been less inclined to moral judgement, seeing Richard's actions as a product of the unstable times. In the words of Charles Ross, "the later fifteenth century in England is now seen as a ruthless and violent age as concerns the upper ranks of society, full of private feuds, intimidation, land-hunger, and litigiousness, and consideration of Richard's life and career against this background has tended to remove him from the lonely pinnacle of Villainy Incarnate on which Shakespeare had placed