The situation was saved in 1911 by the solidarity of England and France. Two Powers, which in the past had been separated by a multitude of prejudices and conflicting ambitions, felt at last that both were exposed to a common danger of the most serious character. Hence a new phase in the Anglo-French _entente_, which was cemented, not by a treaty, but by the interchange of letters between the English Secretary for Foreign Affairs (Sir Edward Grey) and the French Ambassador in London (M. Paul Cambon). On November 22, 1912, Sir Edward Grey[19] reminded M. Cambon of a remark which the latter had made, 'that if either Government had grave reason to expect an unprovoked attack by a third Power, it might become essential to know whether it could in that event depend on the armed assistance of the other.' Sir Edward Grey continued:--'I agree that if either Government had grave reason to expect an unprovoked attack by a third Power, or something that threatened the general peace, it should immediately discuss with the other whether both Governments should act together to prevent aggression and to preserve peace, and, if so, what measures they would be prepared to take in common. If these measures involved action, the plans of the General Staffs would at once be taken into consideration, and the Governments would then decide what effect should be given to them.' M. Cambon replied on the following day that he was authorized to accept the arrangement which Sir E. Grey had offered.[20] The agreement, it will be seen, was of an elastic nature. Neither party was bound to co-operate, even diplomatically, with the other. The undertaking was to discuss any threatening situation, and to take common measures if both agreed to the necessity; there was an admission that the agreement might result in the conduct of a joint defensive war upon a common plan. Such an understanding between two sovereign states could be resented only by a Power which designed to attack one of them without clear provocation.