The indomitable commander now advanced northward along the coast as far as Chiahuitzla, near the roadstead where his ships were anchored. A short distance from this place Cortes began to build the city to which he gave the name Villa Rica de Vera Cruz (the Rich Town of the True Cross). From the port of the new city, Cortes, on the twenty-sixth of July, 1519, dispatched a ship to Spain, under the command of Alonso Puertocarrero and Francisco de Montejo, carrying letters to the emperor, Charles V., with accounts of the invasion of New Spain. With these communications were sent some of the presents that Cortes had received, besides several cotton and agave-scrolls of Mexican hieroglyphics. “Our agents took charge of the letters,” Diaz remarks, “and were bound by a promise not to touch at the Havannah under any pretext whatever, or to enter the harbor of El Marien, where Francisco de Montejo had possessions. This was done in order that Diego Velasquez might not receive any intelligence of our movements.” The resolute officer, having ordered his ships to be destroyed, began about the middle of August his march toward the city of Mexico,[323] with his small band of about five hundred followers, fifteen horsemen, and seven pieces of artillery. He took with him thirteen hundred native warriors from Cempoalla, besides a thousand porters to transport the camp-baggage, provisions, and munition. In the province of Xocotlan the invaders came to an Indian town called by the Spaniards Castilblanco, governed by a cacique who was subject to Montezuma. The hospitable ruler described to Cortes the situation of the city of Mexico, which was built on an island surrounded by water, and approachable on foot by three bridged causeways. “A certain place in this province,” says Diaz, “I shall never forget. Here a vast number of human skulls were piled in the best manner imaginable. There must have been more than one hundred thousand; I repeat, more than one hundred thousand. In the same orderly way the remaining human bones were piled in another corner of the square. The latter it would have been impossible to count. Besides these bones there were human heads hanging from beams on both sides of the square.” On the first, second, and fifth days of September, near the village of Tehuacacinco, Cortes had victorious engagements with the Tlascallans.