Barnabas and Mark left for Cyprus, while Paul and Silas started for Derbe, not as before by sea, but northward, by land, across the mountain known as Amanus, the pass of this range being about twenty miles north of Antioch in Syria. This pass is now known as that of Beilan, which lets the traveller down upon the famous plain of Issus, where, B. C. 333, Alexander the Great had met and defeated the Persian king Darius. Crossing this plain to the extreme northeastern end of the Mediterranean, now called the Gulf of Iskanderun (or Alexandretta), an additional distance of about twenty-five or thirty miles from the mountain pass, they had then the towns of Mopsuesta and Tarsus on the Roman road on the plain directly west as they turned around the corner of the coast.[194] =2. It appears, however=, that they soon reached the pass north of Tarsus, by which they made their ascent to the great high tableland. This pass was probably that of the so-called “Silician Gates,” twenty-two or twenty-three miles north of Tarsus, at the top of which is the supposed site of Derbe, about fifty miles a little north of west, upon the great plain we have before described. =3. From Derbe they passed= westward to Lystra. Here Paul found Timothy, a young convert from the last visit, as mentioned, Acts 16. Thence they came to Iconium. They now left the former route, and judging from the direction of the old roads and general routes of travel between important cities at that time, it is probable that their course was through Laodicea (now called Ladik),[195] Philomelium, and Synnada, the last two known at present as Ak-sher and Eski Kara-hisser, or the “old black castle.” Ladik is twenty-four or five miles northwest of Iconium and has many remains of antiquity. It is now a small place of only 500 inhabitants. Ak-sher, or the “white city” of the Turks, is about sixty-five miles northwest of Iconium and contains about 1,500 houses, and is the Philomelium of Strabo, the geographer. There is a remarkable salt lake ten miles north of it, which is dry in summer and affords much salt at that season, but in the winter is full and extends some twenty or thirty miles westward. =4. The next point= which seems to have been on the course of travel was near the great centre of the present opium manufacture of Asia Minor, namely, the place called “the opium black castle,” or Aphium Kara-hissar of the Turks. This place is on the northern base of a hill on the south side of the river of the Ak-sher lake before spoken of. This river is a small stream whose source is in the hills west of the town, but it is lost in the lake, having no other outlet. Very fine marble quarries existed in this region in ancient times.[196]