Walpole struggled hard, during the ten years following 1729, to keep off war. In that year a treaty signed at Seville professed to regulate matters, restoring the conditions of trade to what they had been four years before, and providing that six thousand Spanish troops should at once occupy the territory of Tuscany and Parma. Walpole argued with his own people that war would lose them the commercial privileges they already enjoyed in Spanish dominions; while with Spain he carried on constant negotiations, seeking concessions and indemnities that might silence the home clamor. In the midst of this period a war broke out concerning the succession to the Polish throne. The father-in-law of the French king was one claimant; Austria supported his opponent. A common hostility to Austria once more drew France and Spain together, and they were joined by the King of Sardinia, who hoped through this alliance to wrest Milan from Austria and add it to his own territory of Piedmont. The neutrality of England and Holland was secured by a promise not to attack the Austrian Netherlands, the possession of any part of which by France was considered to be dangerous to England's sea power. The allied States declared war against Austria in October, 1733, and their armies entered Italy together; but the Spaniards, intent on their long-cherished projects against Naples and Sicily, left the others and turned southward. The two kingdoms were easily and quickly conquered, the invaders having command of the sea and the favor of the population. The second son of the King of Spain was proclaimed king under the title of Carlos III., and the Bourbon Kingdom of the Two Sicilies thus came into existence. Walpole's aversion to war, leading him to abandon a long-standing ally, thus resulted in the transfer of the central Mediterranean to a control necessarily unfriendly to Great Britain.