Conrad III (25 March 1252 – 29 October 1268), called the Younger or the Boy, but usually known by the diminutive Conradin (German: Konradin, Italian: Corradino), was the last direct heir of the House of Hohenstaufen.

On 23 August 1268 his multinational army of Italian, Spanish, Roman, Arab and German troops encountered that of Charles at Tagliacozzo, in a hilly area of central Italy.

The eagerness of Conradin's forces, notably that of the Spanish knights led by Infante Henry of Castile who mounted a triumphant charge and captured the Angevin banner, initially appeared to have secured victory.

But their inability to see through Charles' ruse allowed the latter to ultimately emerge victorious once the elite of his army, the veteran French knights he had hidden behind a hill, entered the battle to the surprise of the enemy.

Escaping from the field of battle, Conradin reached Rome, but acting on advice to leave the city he proceeded to Astura in an attempt to sail for Sicily.

Carmel at Naples, founded by his mother for the good of his soul; and here in 1847 Maximilian, crown prince of Bavaria, erected a marble statue by Bertel Thorvaldsen to his memory.

In the 14th-century Codex Manesse, a collection of medieval German lyrics, preserved at Heidelberg, there appear two songs written by Conradin, and his fate has formed the subject of several dramas.

According to a strict sense of legitimacy,[b] the general heiress of his Kingdom of Sicily and the Duchy of Swabia was his aunt Margaret, half-sister of his father Conrad IV (the youngest but only surviving child of Frederick II and his third wife, Isabella of England) and married with Albert, Landgrave of Thuringia since 1255.

Margrave Frederick proposed an invasion of Italy in 1269, and attracted some support from the Lombard Ghibellines, but his plans were never carried out, and he played no further part in Italian affairs.

[6] Conradin : a philosophical ballad was written by C. R. Ashbee, dedicated to his patron and friend Colonel Shaw Hellier, and published in 1908 by Essex House Press, "one of the most significant private presses at work during the Arts and Crafts movement"[7] The novel Põlev lipp (The Burning Banner) by Karl Ristikivi (1961; in Estonian) depicts Conradin's Italian campaign.