Source:[3] Isnard, from the House of Grasse, Commander of St. John of Jerusalem, Prior of Capua, Grand Seneschal of Provence, in recognition of his services received the lands of Mas and Aiglun from Queen Jeanne on 7 July 1348.

The Grasse family lost the lordship of Mas at the time of the separation of Nice and it subsequently remained with the Counts of Provence.

In 1713 the Treaty of Utrecht provided that Ubaye and its dependencies, formerly under the Kingdom of Piedmont-Sardinia, were exchanged for the French areas in the Susa Valley so that the boundary followed the line of the watershed.

But the overlapping of territories inherited from history remained: Entraunes and Saint-Martin-d'Entraunes were dependent on Barcelonnette but are in the Var valley while the Piedmontese side upstream of Guillaumes was already French.

In addition, in the Estéron Valley the right bank of the Var was Piedmontese which created a tongue of land jutting out into French Provence.