Theobald was the probably legendary Viscount of Béarn in 1171. He was from Bigorre

Bigorre

Bigorre is region in southwest France, historically an independent county and later a French province, located in the upper watershed of the Adour, on the northern slopes of the Pyrenees, part of the larger region known as Gascony...

. The story of his succession to Béarn is probably not reliable and is likely a later invention.

In 1171, the nobles of Béarn repudiated William of Montcada

William I of Béarn

William I, called Guillem de Montcada II, was the Viscount of Béarn from 1171 to 1173 with opposition.William was the eldest son of Guillem Ramon de Montcada II. William first appears in 1150, witnessing his father's settlement at Arles with the Baux family after Raymond Berengar IV of Barcelona's...

, the choice of their lord Alfonso II of Aragon

Alfonso II of Aragon

Alfonso II or Alfons I ; Huesca, 1-25 March 1157 – 25 April 1196), called the Chaste or the Troubadour, was the King of Aragon and Count of Barcelona from 1164 until his death. He was the son of Ramon Berenguer IV of Barcelona and Petronilla of Aragon and the first King of Aragon who was...

 to be their viscount through marriage to the heiress Mary

Mary of Béarn

Mary was the daughter, sister, wife, and mother of various Viscounts of Béarn, Gabardan, and Brulhois. Briefly, from 1170 to 1171, she ruled Béarn as Viscountess in her own right...

. The nobles asked Theobald to be their ruler, but he did not abide by the Fors de Bearn

Fors de Bearn

The Fors de Bearn, or fueros of Béarn, are a series of legal texts compiled over centuries in the Viscounty of Béarn...

 and was executed soon after he took up power. The nobles replaced him with Sentonge

Sentonge of Béarn

Sentonge was the probably legendary Viscount of Béarn from 1171 until his execution two years later. He was from Auvergne. The story of his succession to Béarn is probably not reliable and is likely a later invention....