Things went from bad to worse. In the meantime the French and English had landed at Salonika in order to rush to the aid of the hard-pressed Serbs. You have already been told how Venizelos arranged this. Their aid, however, had come too late. Before they could reach the gallant little Serbian army it had been crushed between the Austrians and Germans on one side and the Bulgarians on the other, and its survivors had fled across the mountains to the coast of Albania. The French and English detachments were not strong enough to stand against the victorious armies of Germany, Austria, and Bulgaria. They began to retreat through southern Serbia. King Constantine notified the Allied governments that if these troops retreated upon Greek soil he would send his army to surround them and hold them as prisoners for the rest of the war. France and England replied by notifying him that if he did this they would blockade the ports of Greece and prevent any ships from entering her harbors. This act on the part of France and England, while it seemed necessary, nevertheless angered the proud Greeks and strengthened the pro-German party in Athens. The king took advantage of this feeling to appoint a number of pro-Germans to important positions in the government. Constantine allowed German submarines to use certain ports in Greece as bases of supply from which they got their oil and provisions. The Greek army was still mobilized, and the small force of French and English, which had retreated to Salonika, were afraid that at any moment they might receive a stab in the back by order of the Greek king. In May, 1916, the Germans and Bulgarians crossed the Greek frontier and demanded the surrender of several Greek forts. When the commander of one of them proposed to fight, the German general told him to call up his government at Athens over the long distance telephone. He did so and was ordered to give up the fort peaceably to the invaders. We have already seen what the answer of the Belgians had been on a like occasion. To be sure, the French and English were already occupying Greek soil, but they had come there under permission of the prime minister of Greece to do a thing which Greece herself had solemnly promised that she would do, namely, to defend Serbia from the Bulgars.