When his forces reached Slankamen in Syrmia, George Martinuzzi begged Mehmed not to attack Transylvania, arguing that it had remained in the possession of the Sultan.

Mehmed rejected negotiation proposals, led Ottoman forces into Transylvania and soon captured 16 cities, including Bečej, Becskerek, Csanád and Lippa.

His position as Governor-General of Rumelia was given to a Herzegovinian Janissary agha, Pertev Pasha, an old companion of Mehmed's from when they had both served under Iskender Çelebi.

One of them was Lala Mustafa, who instigated the Sultan's third son, Bayezid, then Beylerbey of Karaman, to raise a rebellion against his brother and heir-apparent Selim.

The Sultan immediately declared war against the Holy Roman Empire, and Sokollu Mehmed began the preparations for the army's advance.

Nikola Šubić Zrinski (Miklós Zrínyi) had defeated the sanjakbey Tirhal Mohammed, executing him and his son, and capturing 17,000 ducats.

[20] Expecting a mutiny among the military in the capital, Sokollu Mehmed had Suleiman's body sent to Constantinople to restore order amongst the janissaries and other officials, who now demanded more compensation for their past efforts.

Sokollu Mehmed assured him that he would manage everything effectively, and distributed gifts to the troops, rewarding them handsomely to regain their loyalty[citation needed].

Order was restored after Sokollu Mehmed convinced the Sultan to promise to send handsome gifts and higher wages to the janissaries.

Historical records from the time show that Sokollu played an active role in the strategic execution of the invasion and that he was extremely detailed in the logistics.

An uprising led by Zaydi Imam in Yemen created substantial uncertainty in the region which Sokollu had to give imminent priority before taking any further action in Aceh.

[24] While the insurrection in Yemen started in the summer of 1567, it was not taking seriously by the Ottoman regime until later in the year, when most of the major cities in the region came under fire by the rebellious factions.

The unhappiness in the Ottoman Yemen also went back to the rule of Governor Mahmud Pasha, a compatriot of Sokollu, who managed to produce large economic gains in the region at the expense of the wellbeing of the population.

[26][24] Although the rebellions in Yemen once again forced Sokollu to postpone any further military action in Sumatra and the Indian Ocean,[24] it also opened the possibility to promote one of his favorite projects: and attempt to build a canal from the Mediterranean to Suez.

[27] He instructed the governor of Egypt to send architects engineers to assess the possibility of this canal, with the purpose of allowing a better connection from Muslims attempting to visit the Holy Cities.

[24] Sokollu also was concerned about Muslims from the northeast, Crimea and Anatolia, who had to cross the Black Sea in order to visit the Holy Cities.

Sinan Pasha solemnly declared the reign of Sultan Selim II in Mecca upon finishing his military campaign in Hejaz and Yemen.

The invasion of Cyprus led to the formation of a so-called Holy League, comprising the Pope, Spain with Naples and Sicily, the Republic of Venice, Genoa, Tuscany, and the Knights of Malta.

[31] It is reported in Turkish chronicles that Sokollu Mehmed Pasha had said to the Venetian Ambassador "By conquering Cyprus we have cut off one of your arms; at Lepanto by defeating our navy you have only shaved off our beard.

On 3 March 1573, the Venetian Republic signed a new peace treaty with the Ottomans under Mehmed Pasha, thereby bringing the Holy League to an end, accepting the loss of Cyprus and increasing the tribute payments.

He also extended for eight more years the peace treaty with the Holy Roman Empire and maintained good relations with France, Poland-Lithuania and Russia.

Sokollu Mehmed Pasha's wealth reached its peak around 1573, when the value of his personal property (cash, goods, accounts, objects) amounted to 18 million ducats.

[citation needed] On 30 August 1574, Grand Vizier Sokollu Mehmed Pasha installed his nephew Antonije Sokolović, then the Metropolitan of Hum, as the new Eastern Orthodox Archbishop of Ohrid.

[citation needed] Sokollu Mehmed signed numerous treaties of friendship with Venice, Florence, Spain, England and Switzerland.

He also managed to force a number of European states to pay tribute: Austria paid 9,000 ducats; Transylvania 3,000; Wallachia 7,000; Moldavia 3,000.

[1] Sultan Murad III time afterwards, began to limit his Grand Vizier's powers by slowly removing his allies from high offices.

Mehmed's greatest rivals, Hamid Efendi and Piyale Pasha, arranged the execution of the Grand Vizier's Greek protege, Michael Kantakouzenos.

Foundations of his buildings are spread over Edirne, Halep, Medina, Bečkerek, Belgrade and alongside[clarification needed] Bosnia, where he is especially remembered for his bridges.

He also worked together with prominent Ottoman geographers and historians of his time, including Feridun Ahmed Beg, Sipahazade Mahmed, and Kutbeddin Mekki.

Mehmed's nephew, Sokollu Mustafa Pasha, was also a prominent politician, was sanjakbey of Bosnia and later the longest-serving governor of Budin Eyalet.