to
Francis I about the plans for the siege of Nice, written in mid-February 1543 In the Mediterranean, active naval collaboration took place between France and the
Ottoman Empire to fight against Spanish forces. Following an agreement between Francis I and Suleyman the Magnificent, through the intervention of the French ambassador in
Constantinople,
Antoine Escalin des Aimars, best known as Capitan Polin, a fleet of 110 galleys and 50 galiots under
Hayreddin Barbarossa left from the
Sea of Marmara in mid-May 1543. He then raided the coasts of
Sicily and Southern Italy through the month of June, anchoring in front of Rome at the mouth of the
Tiber on 29 June, while Polin wrote reassurances that attacks against Rome would not take place. Meanwhile, Barbarossa went to the harbour of
Toulon on 10 July and then was received with honours at the harbour of
Marseille on 21 July, where he joined the French forces under the Governor of Marseille,
François of Bourbon, Count of Enghien. Barbarossa had originally intended to disembark in Spain, but it was prevented by their failure at
besieging Perpignan and the presence of the imperial fleet under
Andrea Doria in the
gulf of Roses. Charles V had previously gathered 57 galleys and 40
carracks in
Genoa for the occasion. Franco-Ottoman attention turned towards the
Duchy of Savoy, of which Nice was a part. Although Savoy had been a French protectorate for a century, Francis I chose to attack it because
Charles III, Duke of Savoy had angered him by marrying
Beatrice of Portugal, thus becoming an ally of the
Habsburgs. Before Barbarossa's arrival, François de Bourbon had already attempted to make a surprise attack on Nice with ten galleys from Marseille, but had been repulsed by Doria coming with 44 galleys of his own, with four French vessels being captured. In order to besiege the city, Bourbon joined Barbarossa at Marseille in August 1543. Bourbon had reinforced his fleet with 26 galleys and 18 carracks with 7,000 soldiers. The combined fleet sailed out of Marseille on the 5th of August. ==Siege==