Achillas continued to advance toward the city. Cæsar, finding that the crisis which was approaching was becoming very serious in its character, took, himself, the whole command within the capital, and began to make the best arrangements possible under the circumstances of the case to defend himself there. His numbers were altogether too small to defend the whole city against the overwhelming force which was advancing to assail it. He accordingly intrenched his troops in the palaces and in the citadel, and in such other parts of the city as it seemed practicable to defend. He barricaded all the streets and avenues leading to these points, and fortified the gates. Nor did he, while thus doing all in his power to employ the insufficient means of defense already in his hands to the best advantage, neglect the proper exertions for obtaining succor from abroad. He sent off galleys to Syria, to Cyprus, to Rhodes, and to every other point accessible from Alexandria where Roman troops might be expected to be found, urging the authorities there to forward re-enforcements to him with the utmost possible dispatch. During all this time Cleopatra and Ptolemy remained in the palace with Cæsar, both ostensibly co-operating with him in his councils and measures for defending the city from Achillas. Cleopatra, of course, was sincere and in earnest in this co-operation; but Ptolemy's adhesion to the common cause was very little to be relied upon. Although, situated as he was, he was compelled to seem to be on Cæsar's side, he must have secretly desired that Achillas should succeed and Cæsar's plans be overthrown. Pothinus was more active, though not less cautious in his hostility to them. He opened a secret communication with Achillas, sending him information, from time to time, of what took place within the walls, and of the arrangements made there for the defense of the city against him, and gave him also directions how to proceed. He was very wary and sagacious in all these movements, feigning all the time to be on Cæsar's side. He pretended to be very zealously employed in aiding Cæsar to secure more effectually the various points where attacks were to be expected, and in maturing and completing the arrangements for defense. But, notwithstanding all his cunning, he was detected in his double dealing, and his career was suddenly brought to a close, before the great final conflict came on. There was a barber in Cæsar's household, who, for some cause or other, began to suspect Pothinus; and, having little else to do, he employed himself in watching the eunuch's movements and reporting them to Cæsar. Cæsar directed the barber to continue his observations. He did so; his suspicions were soon confirmed, and at length a letter, which Pothinus had written to Achillas, was intercepted and brought to Cæsar. This furnished the necessary proof of what they called his guilt, and Cæsar ordered him to be beheaded.