The lords of Făgăraş will issue from the fortress, over several centuries, numerous diplomas of ennoblement or nobility to the Romanian boyars from Făgăraş County. It must be mentioned that the first document “datum in villa Făgăraş” is from the year 1397 and has been issued by Sigismund of Luxembourg, king of Hungary.

The political role of the fortress increases especially during Mihail Appafy I (1662-1690) when it becomes a genuine princely residence. Between 1670-1691 took place 11 Diets of Transylvania and 18 Delegations (a delegation represented a smaller, restricted, operative, Diet convened for extraordinary cases), while in Alba-Iulia (the official capital city of Transylvania) there were 15 Diets and 3 Delegations.

Ștefan Mailat who was entitled “Liber Dominus terrae Fogaras Voivoda Transilvanus et Siculorum Comes”, assembled in the Făgăraş fortress, for the first time, in 1541, the Diet of Transylvania. Here, in the fortress about which, in 1702, the English reverend Edmund Chishull, being in the suite of the English lord Paget, wrote that it is surrounded by “a wide ditch with water, and it is so strong – or at least defended by luck – that it is said that it has never been conquered through the force of arms”, have been received repeatedly, messengers from Wallachia (1671, 1674, 1675, 1677, 1684, 1685, 1688) or Moldavia (1664, 1666, twice in 1668, 1676, 1678). In 1674 arrived in Făgăraş, as a messenger of the ruler Dumitrașcu Cantacuzino, the great Moldavian chronicler, Miron Costin, who might come back after few years in the suite of the ruler Gheorghe Duca. The importance which Mihail Appafy the First granted to the relations with the two Romanian countries beyond the Carpathians and to the parleys which took place with them also resides in the alliance treaty signed in 1685 with Wallachia, ruled by the voivode Șerban Cantacuzino, treaty approved by the restricted Diet convened in Făgăraş fortress.

In April 1675, it was signed, by the same Prince, the document of the anti-Habsburg treaty with Louis XIV, king of France, a document entitled “Trattato in Fogaras Ii 28 Aprilie 1675 tra di Francesi, Ungari Rebelli et Transilvani contra Sua Mtà Cesarea”. Two years later, a new messenger of king Louis XIV, in the person of Marquis François – Gaston de Béthume, was received in Făgăraş fortress.

Messengers of the Ottoman sultan, of the Grand Vizier, of the Grand Khan of the Tatars, or the Pasha from Timișoara are received here – 1674, 1675, 1676. Ioan Sobieski, as the great Hetman and then king of Poland, will send his messengers multiple times – 1674, 1765, 1676.

Towards the end of the 17th century, there is a major political event for the history of Transylvania – its passing under Habsburg rule. The Diet of Transylvania, on the 13th of May 1688, assembled in Făgăraş, approved the rupture of the vassal relations with the Turks and the passing of the Principality under the protection of the Habsburg Empire. On the 7th of February 1691, in Făgăraş, the Diet of Transylvania accepted Diploma Leopoldinum, which will serve as Transylvania’s Constitution until 1848-1849. Five years later, in 1696, following the order of Emperor Leopold I, the minor Prince Mihail Apaffy II surrenders the city of Făgăraş, receiving back the city of Satu-Mare. From now on, the importance of the fortress decreases, it becoming a simple military garrison.