Peter II of Courtenay is a son of Peter I of Courtenay (d. 1183), the youngest son of Louis VI of France and his second Queen consort Adélaide de Maurienne.

His mother was Elisabeth de Courtenay, daughter of Renaud de Courtenay (d.1194) and Hawise du Donjon.

Peter had first married Agnes of Nevers, via whom he had obtained the three counties of Nevers, Auxerre, and Tonnerre.

He had taken for his second wife Yolanda of Flanders, a sister of Baldwin and Henry of Flanders, who were afterwards the first and second emperors of the Latin Empire of Constantinople.

Peter had accompanied his cousin, King Philip Augustus, on the crusade of 1190 and fought (alongside his brother Robert) in the Albigensian Crusade in 1209 and 1211, when he took part in the siege of Lavaur.

He was present at the Battle of Bouvines in 1214.

When his brother-in-law, the emperor Henry, died without sons in 1216, Peter had been chosen as his successor, and with a small army had set out from France to take possession of his throne.

Consecrated emperor at Rome, in a church outside the walls, by Pope Honorius III on April 9, 1217, he had borrowed some ships from the Venetians, promising in return to conquer Durazzo for them; failing in this enterprise, he had sought to make his way to Constantinople by land.

On the journey, he had been seized by the despot of Epirus, Theodore Komnenos Doukas, and imprisoned.

Because his fate is unknown (although he was probably killed), Peter’s wife, Yolanda, who pregnant with her tenth child, had succeeded in reaching Constantinople, rules as regent.

Peter and Yolanda’s oldest son, Philip II, Marquis of Namur, refuses the empire and it falls to his next oldest brother brother Robert, who like, Philip, is still in France.

Peter dies, probably by foul means, after an imprisonment of two years, and thus never governs his empire.

Yolanda has meanwhile allied with the Bulgarians against the various successor states of the Eastern Roman Empire, and has been able to make peace with Theodore I Lascaris of the Empire of Nicaea, who marries her daughter, Marie, shortly before Yolanda’s death in September, 1219.

Philip II of Courtenay partakes in the Albigensian Crusade of Louis VIII of France and the siege of Avignon in 1226.

The city falls, but epidemics have ravaged the army.

Philip dies near Saint-Flour in the Auvergne.

As he is unmarried, the margraviate goes to his brother Henry.

The eldest son of the Peter II of Courtenay and Yolanda of Flanders, Philip had inherited Namur as the designated heir on the death of his maternal uncle Philip the Noble, in 1212.

He had had to fight the descendants of Henry IV of Luxembourg, who have not given up their claim to Namur.

When Cunigunda, a daughter of Frederick I, Duke of Lorraine and the wife of Waleran III, Duke of Limburg, died in 1214, Waleran had soon wed Ermesinda of Luxembourg, and became count jure uxoris there.

Ermesinda claimed Namur and Waleran had added a crown to his coat of arms to symbolize this claim.

In 1223, Waleran had again tried to take Namur from Philip II, but had failed and signed a peace treaty on February 13 in Dinant.

When Philip's father died in 1217, Philip had refused the crown of the Latin Empire of Constantinople and it had fallen to his brother Robert.