The megas logothetes (Greek: μέγας λογοθέτης, lit. 'Grand Logothete'^{[lower-alpha 1]}) was an official who served as effective foreign minister of the Byzantine Empire, in the period from c. 1250 to c. 1350, after which it continued as an honorific dignity. The office evolved from the Komnenian-era logothetes ton sekreton, and was established during the Empire of Nicaea. Its holders were frequently distinguished scholars, who played a prominent role in the civil and military affairs of their time; three of its holders also served in tandem as the head of the civil administration and effective prime minister (mesazon) of the Empire. The title was also used in the Empire of Trebizond. After the fall of Constantinople, it was adopted in the Danubian Principalities as an honorific title for laymen in the Ecumenical Patriarchate of Constantinople.

The post originated as the logothetes ton sekreton, established by Emperor Alexios I Komnenos (r. 1081–1118) in an attempt to improve the coordination of the various fiscal departments (sekreta).^[1][2] In the late 12th century, the logothetes ton sekreton had risen to a pre-eminent position among the civil administrators, and was increasingly called the megas logothetes to indicate this.^[3] The all-powerful logothetes ton sekreton Theodore Kastamonites, maternal uncle and de facto regent of the Empire during the early reign of Isaac II Angelos (r. 1185–1195, 1203–1204), was the first to be officially called megas logothetes in a chrysobull of 1192, although as a honorific rather than an actual new title.^[4]

The logothetes ton sekreton was not formally replaced by the designation megas logothetes until after 1204, in the Empire of Nicaea (1204–1261) and under the revived Byzantine Empire under the Palaiologos dynasty (1261–1453).^[5] As seen in the case of the first known megas logothetes, Strategopoulos, in c. 1217, the post apparently retained its previous role: Strategopoulos is mentioned as president of the imperial tribunal, apparently the same body attested in 1196 under the presidency of the logothetes ton sekreton.^[6][7]

By the middle of the 13th century, however, its functions had evolved to become completely different from his antecedent: the megas logothetes assumed the conduct of foreign affairs and headed the chancery involved with diplomatic correspondence, previously the purview of the logothetes tou dromou.^[7][8][9] The megas logothetes was thus unique among the logothetes in retaining both its exalted position and an active function during the early Palaiologan period: the Book of Offices of pseudo-Kodinos, one of the main sources for the late Byzantine court and administration, records the logothetes tou genikou, logothetes tou dromou, logothetes tou stratiotikou, and logothetes ton agelon as purely honorific titles without a function. Pseudo-Kodinos wrote shortly after the middle of the 14th century, but the situation he records is likely of even earlier date.^[10]

Since the publication of Charles Diehl's study on the logothetes ton sekreton in 1933, a generation of scholars considered the megas logothetes as the de facto chief minister of the Palaiologan-era Byzantine Empire.^[11] This view, however, has been proven as mistaken by later studies: numerous sources show that the position of chief minister during that time was designated by the title of mesazon, an office that supervised the imperial chancery and was in charge of state administration and justice.^[12][13][14] Indeed, Pseudo-Kodinos explicitly points out that the "proper function" of the megas logothetes was to supervise "the prostagmata and chrysoboulla sent by the emperor to all kings, sultans and toparchs", while the mesastikion (the function of a mesazon) "is carried out by whoever the emperor commands".^[15] Only three megaloi logothetai are known to have held the mesastikion—Theodore Mouzalon, Theodore Metochites, and John Gabalas—and indeed appear to have been appointed as mesazon before being promoted to megas logothetes, thereby demonstrating the distinct nature of the two titles.^[11][16] Already during pseudo-Kodinos's time, however, the purview of foreign affairs had been transferred to the mesazon, and the megas logothetes was thereafter reduced to a mostly honorific position; the early 15th-century writer Mazaris describes it as a 'prize' (γέρας) without particular attributes.^[7]

In his Untersuchungen zur spätbyzantinischen Verfassungs- und Wirtschaftsgeschichte, the German scholar Ernst Stein proposed that in the early 14th century, the megas logothetes also exercised the functions of the former Eparch of Constantinople in overseeing the administration of the imperial capital, until Andronikos III Palaiologos (r. 1328–1341), seeking to secure his throne after winning the civil war of 1321–1328, assigned them to the protostrator. Stein's assumption relies on reading the mesastikion in the passage of Pseudo-Kodinos as a compound denoting the Mese boulevard (which Stein considered as the centre of the capital's administration) and the rest of the city, rather than relating it with the office of mesazon; Stein's interpretation has been disproved by scholars such as Hans-Georg Beck and Léon-Pierre Raybaud.^[17][18]

Originally, the title ranked twelfth in the overall hierarchy of the palace, between the megas konostaulos and the protosebastos, but in March/April 1321 Emperor Andronikos II Palaiologos (r. 1282–1328), wishing to exalt his favourite Theodore Metochites, promoted him from logothetes tou genikou and raised the rank further to ninth place, above the megas stratopedarches and below the protostrator. It appears that the rank retained this high position for the remainder of the Byzantine Empire's existence.^[19][20]

According to pseudo-Kodinos, the insignia of office were a rich silk kabbadion (a kaftan-like tunic), a golden-red brimmed hat (skiadion) decorated with embroideries in the klapoton style, without veil, or a domed skaranikon hat, again in red and gold and decorated with golden wire, with a portrait of the emperor standing in front, and another of him enthroned in the rear. Unlike most officials of the court, he bore no staff of office (dikanikion).^[21]

Following the Fall of Constantinople in 1453, the title was used in the Danubian principalities of Moldavia and Wallachia. In the former, the Great Logothete (mare logofăt) was the chief minister of the prince and head of the chancellery, while in Wallachia, he was the second-most senior member of the prince's council, after the ban.^[22] To this day, the leading rank among the lay archons of the Ecumenical Patriarchate of Constantinople bears the title of "Grand Logothete".^[23]