The South Caucasus, especially Azerbaijan, has always been in the spotlight because of its rich natural resources, raw material resources, as well as its important strategic geographical position.
  
In addition to its economic importance, Azerbaijan, occupying an important position in the Caucasus, was of great strategic interest by playing the role of a bridge connecting Europe and Asia. Extremely important military-strategic and trade routes passed through the territory of Azerbaijan. There were also seaports here, which were significant for Russia's access to eastern countries. The occupation of Azerbaijan, particularly its Caspian Sea coastal provinces by the Ottoman Empire, would have cut off Russia's access to several eastern countries. For Russia, it also meant the loss of an important line of communication linking it with the Safavid state. 

In the early 18th century, the Caspian Sea was the only southern sea to which Russia had free access. Peter the Great tried to turn Russia into an intermediary state for trade between East and West. 
        
In August 1721, when the Shirvan rebels led by Haji Davud and their allies Surkhay khan Gazigumuglu seized the city of Shamakhi, five Russian merchants were killed, and their property was looted.
 
The murder and robbery of Russian merchants in Shamakhi became a convenient pretext for Peter the Great, Tsar of Russia who was looking for an opportunity to seize Azerbaijan and some other territories of the Safavid state.

Peter the Great issued a "Manifesto" and sent it to the cities and villages located in the line of march of the Russian army in order to "explain" the reason for the advance among the inhabitants of the Caspian provinces. The real reason for the march was covered up in the manifesto,  and it was stated that the purpose of the Russian army in this march was to take vengeance for the Russian merchants who were murdered and robbed in Shamakhi during the Shirvan rebellion, as well as to administer punishment to the rebels, especially Haji Davud and Surkhay khan who rose up against the Shah of Iran, a friend of the Russian state.  Peter the Great also promised peace to the local population in his Manifesto. The Manifesto was also printed in Azerbaijani. 
       
On August 23, 1722, Russian troops entered the city of Derbent without encountering any resistance. The Viceroy of the city Imamgulu presented two silver keys of Derbent Castle to Peter the Great in order to remain in office. On August 30, the Russian army moved from Derbent to Baku. However, due to several reasons, Peter the Great stopped his march and returned to Derbent on September 5. On September 7, he left the garrison there under the leadership of Colonel Yunger and returned to Russia.
  
Peter the Great decided to continue the occupation of the provinces located in the west and south of the Caspian coast by sending military expeditions. Since the Afghans, who had captured Isfahan in October 1722, were soon expected to move on to Gilan, the Russians quickly occupied the place. In December 1722, the Russian squadron headed by Colonel Shipov entered the port of Anzali and captured the city of Rasht meeting with no resistance.
    
Taking advantage of the collapse of the Safavid Empire, the Ottoman Empire also sent its troops to the South Caucasus. Diplomats of Western European countries tried to convince the sultan that Georgians and Armenians under Ottoman rule, would accept Russian subordination if the Russians took over the provinces of Shirvan and Iravan.        
The threat of the occupation of the entire South Caucasus by the Ottoman state prompted Peter the Great to seize Baku. On July 21, 1723, the Russian fleet entered Baku port. Despite strong resistance, the Baku garrison could not withstand the attack of the enemy, who had a large army and military equipment, and was forced to surrender the fortress to the foreign invaders led by General Matyushkin to prevent the fire and losses that would have occurred in the city because of the artillery bombardment. Sultan of Baku Mahammad Huseyn bey was arrested with his brothers and exiled to Russia. Colonel Baryatinsky was appointed commandant of the city. The Russians easily occupied the city of Salyan after Baku.
          
After the Russian troops occupied a part of the Caspian Sea coastal provinces, Peter the Great offered Ismayil bey, the former envoy of Iran, who had been deprived of his powers by Tahmasib II, an agreement on the territorial concessions of the Iranian state to Russia with the lands from Derbent to Gilan, as well as Shamakhi, Mazandaran and Astrabad. On September 12, 1723, a treaty was signed with Russia in Petersburg based on the specified conditions. In return, Russia undertook to provide military assistance to the Safavid shah to protect his power. Tahmasib II categorically refused to approve this agreement, which lacked a legal basis in advance. Ismail bey was declared a traitor. He did not dare to return and remained in Russia until the end of his life.
   
The entry of Ottoman troops into the territory of Azerbaijan and their advance to the east created the danger of a clash against the Russian troops stationed in the Caspian Sea coastal provinces. However, Russia, unwilling to go to war with the Ottomans, offered the Ottoman Empire to sign a treaty on the division of the region. After long negotiations and disputes, the parties agreed to divide the Safavid heritage. On July 12, 1724, a treaty was signed with Russia in Istanbul. According to the agreement, the Ottoman side confirmed the Caspian Sea coastal provinces occupied by Russia "as concessions made by Iran to Russia". Russia, in its turn, stated that it would not oppose to the occupation of the Western Caucasus and South Azerbaijan by the Ottomans. According to one of the articles of the Treaty of Istanbul, except for the Caspian provinces, the remaining part of Shirvan was known as a khanate under the supreme power of the sultan.
      
Thus, the first stage of the occupation of the Caspian Sea coastal provinces by Russia was completed.            

Recommended literature:

1. Quliyev, Ə. N. Azərbaycan-Rusiya münasibətləri tarixindən : XV-XVIII əsrlər / Ə. N. Quliyev ; bur. məsul V. Bəhmənli ; red. Ə. Əsədzadə ; Azərbaycan Respublikası Mədəniyyət və Turizm Nazirliyi, Azərbaycan Milli Kitabxanası. - Bərpanəşr. - Bakı : Renessans-A, 2015. - 56 s.
2. Nəcəfli, Güntəkin Cəmil qızı. XVIII əsrdə Azərbaycan ərazisində erməni dövləti yaradılması cəhdləri : monoqrafiya / G. C. Nəcəfli ; elmi red. T. T. Mustafazadə ; AMEA A.A. Bakıxanov adına Tarix İnstitutu. - Bakı : Nurlan, 2007. - 248 s.
3. Baxşəliyev, Tahir Şamil oğlu. Rusiya tarixi ən qədim zamanlardan günümüzədək : bakalavr pilləsi üçün dərslik / T. Ş. Bəxşəliyev ; elmi red. C. M. Cəfərov ; Bakı Dövlət Universiteti. - Bakı: Təhsil, 2021. - 808 s. 
4. Azərbaycan tarixi. Yeddi cilddə. III cild (XIII-XVIII əsrlər). Bakı: "Elm", 2007. - 592 s.
5. Шишов, Алексей Васильевич. Схватка за Кавказ: XVI - XX века / А. В. Шишов. - М. : ИД Вече, 2005. - 448 с.
6. Куликов, Анатолий Сергеевич. Все кавказские войны России : самая полная энциклопедия / А. С. Куликов, В. А. Рунов; отв. ред. А. Климова. - М.: Яуза : Эксмо, 2013. - 608 с.
7. Курукин, И.В. Персидский поход Петра Великого. Низовой корпус на берегах Каспия (1722-1735 гг.) / И.В. Курукин– М. Квадрига; Объединённая редакция МВД России, 2010. - 381 с.