during the
Persian embassy to Europe (1599–1602). Finally, on 18 February 1529,
Charles V, deeply alarmed by the
Ottoman progression towards Vienna, again sent a letter from
Toledo to Shah Ismail, who had died in 1524 and had been replaced by
Shah Tahmasp, pleading for a military diversion. Tahmasp also responded by expressing his friendship to the Emperor. but Balbi took more than one year to return to the Persian Empire, and by that time the situation had changed in Persia, as Persia was forced to make peace with the Ottoman Empire because of an insurrection of the
Shaybanid Uzbeks. From that time, as soon as the Ottomans would launch a European campaign, they would be attacked by the Persians on their eastern frontier, forcing Suleiman to return speedily to his capital. Meanwhile, King
Francis I of France, enemy of the Habsburgs, and
Suleiman the Magnificent were moving forward with a
Franco-Ottoman alliance, formalized in 1536, that would counterbalance the Habsburg threat. In 1547, when Suleiman attacked Persia, France sent him the ambassador
Gabriel de Luetz to accompany him in his campaign. Gabriel de Luetz was able to give decisive military advice to Suleiman, as when he advised on artillery placement during the
Siege of Vān. ==Further attempts==