Hossein Ali Beg Bayat (, ) was a Safavid diplomat who served as the ambassador to the Holy Roman Empire, the Russian Tsardom, Habsburg Spain and several other royal and noble courts during the reign of king Abbas I (r. 1588–1628), and was part of the first Safavid embassy to Europe.

Career He was a member of Turkoman Bayat clan and was born in Sistan province of Safavid Iran. Already an elderly man by the time he was appointed as an ambassador, he was described as a captain of 200-300 soldiers by Michel Angelo Corai and a close member of royal household. His nephew Ali Qoli beg was a friend of Oruj beg Bayat, both of whom would later join him in the diplomatic mission.

When king Abbas I decided to send Sir Anthony Shirley on an important diplomatic mission in Europe, in order to gain support and to form an alliance against the common cause, the Ottoman enemy, Anthony asked the king to send with him an Iranian of rank. Abbas chose a Qizilbash noble, Hossein Ali Beg, and, according to historian David Blow, he seems to have made him the official leader of the mission. However, this matter was apparently never made clear to Sir Anthony or he simply refused to accept it. This would be the reason for a constant unpleasant atmosphere that would sometimes culminate in bitter disputes between the two over precedence. Sir Robert Shirley, who was Abbas' initial choice instead of his brother Sir Anthony, stayed in Iran as a hostage.

In Russia Hossein Ali Beg and Shirley were accompanied by friars Alfonso Cordero, Nicolas de Melo, four secretaries, including Hossein Ali Beg's nephew Ali Qoli Beg, Oruj beg Bayat (later Don Juan), Bunyad bey, nineteen members of Sir Anthony's original suite.Hossein Ali Beg additionally took a number servants with him. It is indeterminate when the diplomatic entourage departed from Isfahan. Pietro Duodo, Venice’s ambassador to the Holy Roman Empire, indicated the date as 24 May, whilst Oruj bey Bayat proposed 9 July. Duodo's account provides the identical date as the credential letters from Shah Abbas received by Shirley in Gilan. Consequently, 24 May 1599 ought to be regarded as the date of the embassy's departure. Given that the embassy traversed the Isfahan-Dowlatabad-Kashan-Qom-Saveh-Qazvin route to reach Gilan, their departure from Isfahan probably occurred at the beginning of May. The remaining members of Shirley’s contingent—Anthony’s brother Robert, John Ward, John Perrot, and Gabriel Brooks, already mentioned—departed from Dowlatabad and resided at the palace of Shah Abbas.

Hossein Ali bey failed to intercept the caravan departing from Isfahan and only encountered Shirley in Gilan. The embassy stayed in Gilan until the conclusion of June because of adverse weather conditions. Oruj bey Bayat's papers indicate that the embassy encountered a storm on the Caspian Sea after departing from Rudsar and arrived at Astrakhan via Mankyshlak in mid-September. It thereafter encountered Pirgulu beg, who had been dispatched as an ambassador to Russia. After a 16-day stay in Astrakhan, they departed for Nizhny Novgorod on the Volga River on a five-oared boat. The embassy, en route to Moscow through Kazan, experienced a delay of seven weeks. The embassy of Hossein Ali bey was intended to proceed to Poland from this location. Tsar Boris Godunov seemingly prohibited their travel to Poland deliberately. Apparently Nicolas de Melo and Anthony Shirley started to have a dispute in Russia, Hossein Ali beg tried to mediate between the sides unsuccessfully. Melo was eventually arrested and exiled to Solovetsky Monastery in Northern Russia.

The embassy, having spent the winter months in Moscow, ultimately reached Arkhangelsk through Yaroslavl, Rybinsk, Totma, Turavets, and Kholmagory route. Following a 20-day sojourn, the embassy, having discovered a Flemish vessel, dispatched thirty-two boxes of gifts directly to Rome at Shirley's recommendation before to their departure. Nonetheless, these gifts did not arrive in Rome. Oruj Bey Bayat suggested that Shirley indeed sold these things to the captain. Shirley on the other hand, claimed that the presents were unworthy of European rulers because to their inferior quality, prompting him to return them to Iran.

In Holy Roman Empire The embassy traveled from Arkhangelsk down the Norwegian coast to Stade, a Hanseatic city located at the Elbe River's mouth. The embassy departed for Emden in August. The mission was met by Count Enno III of East Frisia. Despite Enno's oversight in notifying the emperor on the embassy, Hossein Ali bey dispatched a messenger. The embassy members, who arrived in Oldenburg via the Aurich-Friedeburg-Neuenburg route, encountered John VII, Count of Oldenburg there. They landed in Kassel from Oldenburg on 14 September and met Maurice, Landgrave of Hesse-Kassel according to court historian Wilhelm Dilich. Maurice dispatched a three-horse carriage to greet them at the palace. The diplomats were hosted by the landgrave for ten days; Maurice showcased the chambers of his palace, provided a private tour of the alabaster room, the cabinet of valuable stones adorned with coral walls, the armory, the stables, and exhibited the city’s new cannons. At the formal dining table in the hall, he presented them with fruit, forks, and marzipan shaped as "salt." The embassy members initially failed to comprehend the flavor and laughed. Maurice staged a jousting event in which his son participated prominently. They stayed in Kassel for 8 days and later proceeded eastward through Weimar-Alsfeld, and arrived at Rothenburg an der Fulda on 30 September, traversing Schmalkalden, Gotha, and Erfurt, before continuing to Naumburg the following day. His entrance to Naumburg on was witnessed by Johannes Burger, deacon at St. Wenzel's Church who described the event in his Annalium Naumburgensium. After staying in the famous inn called "Zu den drei Schwanen" (currently, in Jakobsstraße quarter of Naumburg) overnight.

Huseyn Ali bey attempted to confer with Elector Christian II of Saxony in Leipzig; however, the duke disregarded the meeting, prompting the ambassadors to depart for Prague. Hossein Ali beg passed through rest of Saxony and stopped in Louny for lunch. The embassy left in the evening and rested for 3 days at Modletický House in Slaný. The ambassadors departed from Slaný on 10 October and reached the Stella Pavilion (modern Letohrádek Hvězda) in western Prague. The Holy Roman Emperor Rudolf II organized an elaborate welcome for the ambassadors with a parade of 300 horsemen. In Prague, they lodged at "Mad Man" () hotel, owned by the Přehořovský family, situated on modern Karmelitská street. Oruj Bey referred to this Renaissance-style hotel as "a palace." The embassy resided there for one week. During that week, Hossein Ali bey convened with the ambassadors of several nations. Subsequently, Huseyn Ali bey visited Prague Castle multiple times upon special invitation, with the emperor's attendants arranging a customary tour for esteemed guests. The embassy representatives toured the armory, the museum of curiosities including diverse animals and natural artifacts, the imperial wardrobe, the stables, and the lions' den.

The embassy of Hossein Ali bey was prepared to depart from Prague on 17 November. The emperor counseled the diplomat to return to Iran. The emperor could also convey the Shah's letters through his messengers as per his recommendation - a suggestion that Hossein Ali bey declined. Hossein Ali, who had remained in Prague for three days, sought the emperor's assurance for the partnership. Another stipulation of the embassy was more stringent: should war ensue, the emperor could not negotiate peace without the shah's awareness. Hossein Ali bey remained in Prague on 18 December. The Habsburg court attempted to convey to him that when the emperor desired peace, he could not promptly dispatch a courier to the shah - due to the potential for a letter to take months to arrive in Iran. The Germans anticipated a dragoman to interpret the correspondence. Dr. Bartholomew Petzen's sluggishness as an interpreter allegedly exasperated Rudolf II.

Prior to their departure, Rudolf II commissioned the renowned Flemish engraver Aegidius Sadeler to create a portrait of both ambassadors. The emperor's horse-drawn carriages from Prague were escorted by Rudolph's retinue to the town of Beroun, some 25 kilometers distant. The embassy finally departed 5 February. According to Franz Babinger, they entered Bavaria via the Rokycany, Plzen, Kladruby, Přimda route. Following the alternative southern route to the Golden Route () - the traditional route of the Holy Roman Emperors to travel from Prague to Nuremberg - they passed through Waidhaus, Vohenstrauss, Hirschau and Hahnbach and stopped in the city of Sulzbach to spend the night. According to Oruj Bey, the embassy was hosted well by Otto Henry, Count Palatine of Sulzbach.

The next morning, the embassy left for the city of Herzburg and entered Nuremberg, passing through the city of Lauf an der Pegnitz. The embassy entered Nuremberg on 12 February according to Oruj Bey (although, a local chronicler mentioned Candlemas - 2 February 1601). They were lodged at an inn called Bitterholtz (destroyed after bombardment of the city in 1945) for three days and were taken to the armory and to the grain storage facility there. After leaving the city, they continued along Via Imperii to reach Augsburg where they stayed for 6 days. Hossein Ali bey was later received by Maximilian I, Elector of Bavaria in Munich and was hosted for three days. Continuing the route, Hossein Ali finally reached Mantua and was hosted by Vincenzo I Gonzaga where they were joined by Safavid spy Michel Angelo Corai. Hossein, planning to visit Venice, sent Corai ahead to notify Signoria. The embassy, having awaited official authorization from the Doge for three days in Verona, got unforeseen information: Venice was presently accommodating an Ottoman envoy, rendering the Safavid ambassadors unwelcome. According to, Oruj bey this incited Huseyn Ali bey’s fury, perceiving it as an affront.

In Italy

Tuscany On 16 March 1601, the diplomats landed in Florence, the capital of the Grand Duchy of Tuscany. Ennea Vaini of Imola, the Medici's butler, received them in the village of Scarperia. As Shirley traversed the village of Pratolino, he galloped his horse, aiming to reach Florence before Hossein Ali bey, which aroused Ennea Vaini's suspicion that Shirley might not be the primary ambassador. The embassy spent the night at the Pitti Palace. Vaini selected accommodations for Shirley and Hossein Ali directly across from each other. Hossein Ali bey and his entourage used four rooms adjacent to the guest hall, while Shirley and his followers resided in four rooms adjacent to the ducal chapel. On 19 March, the ambassadors departed with Vaini and reached Pisa, where the grand duke was residing. Grand Duke Ferdinando was to meet the diplomats along the Arno River at the Medici Palace, currently known as the National Museum of the Royal Palace. The initial individual to welcome the ambassadors at the palace was Giovanni de’ Medici, the duke's illegitimate brother. Upon the embassy's arrival at the palace late in the evening, Giovanni escorted them to their accommodations on the side of the palace adjacent to the church of San Nicola. The rivalry between Shirley and Hossein Ali Bey manifested in Tuscany as well. Shirley saw the duke individually and presented him with a letter claiming to be from Shah Abbas. Oruj Bey provides no information regarding this letter, which is entirely composed in Italian and preserved in the Florentine archives. Hossein Ali Bey indicated that Shah Abbas did not compose a specific letter for Ferdinando.