Anguissola also influenced the artistic works of her children, Isabella Clara Eugenia and Caterina Michaela, during her time at the court. Philip was completely enchanted by his 14-year-old bride, and by 1564 had given up his infidelities. Despite the significant age difference, Elisabeth was also quite pleased with her husband. (In letters to her mother, she proclaimed herself to be fortunate to have married so charming a prince.) Philip enjoyed hosting chivalric tournaments to entertain his wife. Elisabeth would play liege lady to the three young princes of the Spanish Court: Carlos, Prince of Asturias, John of Austria (illegitimate son of Charles V), and Alexander Farnese, Duke of Parma (son of Charles V's illegitimate daughter Margaret). Elisabeth had originally been betrothed to Philip's son, Carlos, Prince of Asturias, but political complications unexpectedly necessitated instead a marriage to Philip. Her relationship with her troubled stepson Carlos was warm and friendly. Despite reports of his progressively bizarre behavior, Carlos was always kind and gentle to Elisabeth. When it eventually became necessary for Philip to lock him away (which shortly led to the Prince's demise), Elisabeth cried for days. Philip was very attached to Elisabeth, staying close by her side even when she was ill with smallpox. Elisabeth's first pregnancy in 1560 resulted in a stillborn son, followed in 1564 with a miscarriage of twin girls. She later gave birth to Infanta Isabella Clara Eugenia of Spain on 12 August 1566, and then to Isabella's younger sister Catherine Michelle of Spain on 10 October 1567. Phillip and Elisabeth were very close to both of their daughters buying them jams, dolls, toys and more. It is said "both rejoiced at the birth of Isabella as if it had been the birth of a son". Elisabeth had another miscarriage on 3 October 1568, and died the same day, along with her newborn infant daughter. After the death of Elisabeth, Catherine de' Medici offered her younger daughter Margaret as a bride for Philip. Philip declined the offer. In fiction Elisabeth of Valois is a central character in Thomas Otway's play Don Carlos, Prince of Spain; in Schiller's play of the same name; in Verdi's opera adapted from Schiller's play, also titled Don Carlos; and in several other, less well-known operas. Antonio Buzzolla's version of 1850 is actually named "Elisabetta di Valois". All these works imply a tragic romance between Elisabeth and Carlos, suggesting that they were