Casas del Tratado de Tordesillas, Historical monument in Tordesillas, Spain.

The Casas del Tratado de Tordesillas are two joined palaces in Tordesillas, in the province of Valladolid. The older palace dates from the late 15th century and still carries the coat of arms of the Catholic Monarchs on its facade. The second palace was built in the mid-17th century as the residence of a wealthy family.

In 1494, the older of the two palaces hosted the negotiations that led to the Treaty of Tordesillas, an agreement between Spain and Portugal dividing newly discovered territories between them. The treaty shaped the course of colonization across the Americas and Africa for generations.

The entrance still displays the royal crests of the Catholic Monarchs alongside the heraldic symbols of local noble families. These carved emblems give a sense of the social standing that once defined life in this building.

The building now houses a museum dedicated to the Treaty of Tordesillas and the geographical discoveries of the 15th century. Both palace sections are connected inside, so a single visit covers the full complex without needing to go back outside.

The Portuguese ambassadors received secret reports from Lisbon on Castile's negotiating position, along with direct instructions from King John II, according to the chronicler Garcia de Resende. The talks ran for several months in Tordesillas before the treaty was signed on 7 June 1494.