Adventures of Don Juan (1948) on Netflix

The great lover Don Juan comes to the assistance of his queen.

Don Juan de Marana damages Spanish prestige in diplomatic circles with his indiscreet womanizing,although he attempts to rehabilitate his image after he meets the beautiful Queen Margaret, trapped in a loveless arranged marriage with the weak and feckless King Philip III. The Queen becomes the love of Don Juan's life, and although she is obviously attracted to him, the relationship remains appropriately platonic. Becoming caught up in court intrigue, Don Juan uncovers a plot by the King's minister, the ruthless Duke de Lorca, to become the power behind the throne. After de Lorca is exposed by Don Juan, he brazenly intimidates the cowardly king into compliance and threatens to execute the uncooperative queen. Helped by his friends, his servant Leporello, fencing master Don Serafino, and court jester Sebastian, Don Juan tries to foil the Duke's evil machinations.

—duke1029

In the end of the Seventeenth Century, Don Juan de Marana is repatriated from London to Madrid after a serious diplomatic scandal caused by his affair with a British fiancée on the Eve of her marriage with a Spanish noble. The Spanish ambassador in London Count de Polan sends a recommendation letter to his friend Queen Margaret to give an opportunity in the court to rehabilitate Don Juan from the gossips and rumors about his love affairs, and he is hired as instructor of the art of fencing in the Spanish Academy. He secretly falls in love for Queen Margareth but becomes loyal to her and her irresponsible and weak husband, King Phillip III. Don Juan discovers the plan of the Machiavellian Duke de Lorca (that intends to declare war to England and rules Spain. With the support of his friends, Don Juan defends the Queen, the King and Count de Polan against Duke de Lorca and his men.

—Claudio Carvalho, Rio de Janeiro, Brazil