Claude II de Lorraine, duc d'Aumale (18 August 1526, Joinville – 3 March 1573, La Rochelle) was a Prince étranger, military commander and French governor, during the latter Italian Wars and the early French Wars of Religion. The son of the first Duke of Guise he started his career in a pre-eminent position in French politics as a son of one of the leading families in the court of Henri II of France. Upon the death of his father in 1550, Aumale inherited the governorship of Burgundy from his father, and the duchy of Aumale from his brother who assumed the titles of Guise. Aumale was made colonel-general of the light horse by the new king and fought in Italy, Alsace and Picardie between 1551 and 1559. While leading the light cavalry during the defence of Metz he was captured, and held for the next two years, until his mother in law Diane de Poitiers paid his ransom. He achieved success at the siege of Volpiano and played an important role in the capture of Calais for which he was rewarded with the governorship of French Piedmont.

With the death of Henri II he found himself further pushed into prominence in the Guise regime for the young François II. He took part in the effort to suppress the Conspiracy of Amboise that threatened to topple the regime in early 1560. He played a key role in the organisation of the expedition to Scotland in 1560, however the instability that racked the country in the wake of the conspiracy in combination with financial issues ensured the cancellation of the expedition, in December of that year the king died and the Guise regime was displaced by a regency under Catherine de Medici. Alienated by the new regime he departed court in early 1561, before returning as part of his brother Charles, Cardinal of Lorraine's attempted policy of religious reconciliation at the Colloquy of Poissy, the failure of this and the increasing Protestant nature of Catherine's inner circle led to him leading the family into a second exile from court. In early 1562 he was with his brothers at their meeting with the Duke of Württemberg where the topic of uniting around the Lutheran creed was broached. Any hope of this policy was shattered on the return to the capital, where Guise's men committed a Massacre of Protestant worshippers at Wassy.

This served as the instigating incident for the French Wars of Religion. Aumale served the crown throughout the first war, repeatedly trying to besiege Rouen without success, before the main royal army arrived with sufficient force to subdue the town. He failed to stop François de Coligny d'Andelot bringing mercenaries into the kingdom to reinforce the rebel cause. He was wounded at the Battle of Dreux in December. In January his brother was assassinated, leaving him and Lorraine as heads of the family. Guise's son inherited his governorship of Champagne. Aumale would act as de facto governor until the young Guise attained his majority. He played a far more active role in the governance of Champagne than his own government of Burgundy. Meanwhile he and his family prosecuted a bitter vendetta against Gaspard II de Coligny who they blamed for the assassination of Guise. This culminated in skirmishes in Paris, before the king was able to enforce a peace in 1566 between the parties. Aumale continued to fight in the second and third civil wars, but was repeatedly unable to stop incursions into France by German reiters in favour of the rebels. While he was not involved in the planning of the liquidation of the Protestant leadership he was intimately involved in the killing of the Protestant leaders on 24 August 1572 that would spiral out of control into the Massacre of Saint Bartholomew. The following year he was among the nobles present at the siege of La Rochelle where he was killed on 3 March 1573.

Claude II de Lorraine, duc d'Aumale, was born in 1526, the third son of Claude, Duke of Guise and Antoinette de Bourbon. The eldest son François, Duke of Guise was 7 years his elder, while Charles, Cardinal of Lorraine was born in 1524. Louis I, Cardinal of Guise was born in 1527, while François de Lorraine was born in 1534. The youngest Guise son René, Marquis of Elbeuf was born in 1536. Meanwhile his sisters Mary of Guise, Louise of Guise, Reneé of Guise and Antoinette of Guise were born in 1515, 1520, 1522 and 1531 respectively.

On 1 August 1547 he married Louise de Brézé (c. 1518 – January 1577), dame d'Anet, the daughter of Louis de Brézé, seigneur d'Anet, and Diane de Poitiers in one of the key political marriages of the decade. Diane gifted her new son in law Rhuys and Sucinio in Bretagne. She further favoured him with her Norman possessions. The Duke of Guise inquired of Gaspard II de Coligny as to his opinions on the marriage, Coligny replied that he felt Aumale had debased himself by marrying for profit as opposed to the honour of his family. Guise retorted that Coligny was jealous.

The de Bréze inheritance took a considerable time to settle. Aumale and Louise traded Mauny for Anet with the other heirs, the La Marcks. The La Marcks' poor financial situation allowed them to purchase the County of Maulévrier and Barony of Bee Crespin in 1562. Henri-Robert de la Marck was compelled into this by the debts he had acquired as the result of his father's ransom. Aumale continued to acquire land in Normandie until by the late 1560s he was one of the great landholders of upper Normandie.

They had:

At the beginning of Henri II's reign, the king was faced with revolts against the Gabelle tax in the Garrone. To this end he dispatched his favourite Anne de Montmorency alongside François, Duke of Guise and Aumale. Together they achieved success in suppressing the tax revolt. That same year the king elevated the marquisate of Aumale to a duchy for its current holder, Guise. Aumale for his part held the marquisate of Mayenne. In May 1547 Aumale was made a Chevalier de l'ordre de Saint-Michel and in either 1548 or 1549 he became colonel general of the light cavalry.