The city currently known as Mexico City was created by the Mexica people, later known as the Aztecs, in 1325. The old Mexica city that is now referred to as Tenochtitlan was built on an island in the center of the inland lake system of the Valley of Mexico, which it shared with a smaller city-state called Tlatelolco. It is sometimes seen in the scholarly literature written as "Tenochtitlan-Tlatelolco".[23] The great Aztec market that conqueror Bernal Díaz del Castillo describes in detailed wonderment in his chronicle The True History of the Conquest of Mexico is, in fact, describing the market located in Tlatelolco. The Mexica were one of the last of the Nahuatl-speaking peoples who migrated to this part of the Valley of Mexico after the fall of the Toltec Empire. Their presence was resisted by the peoples who were already in the valley, but the Mexica were able to establish a city on a small island on the western side of Lake Texcoco. The Mexica themselves had a story about how their city was founded, after being led to the island by their principal god, Huitzilopochtli. According to the story, the god indicated the site where they were to build their home with a sign - an eagle perched on a nopal cactus with a snake in its beak. Between 1325 and 1521, Tenochtitlan grew in size and strength, eventually dominating the other city-states around Lake Texcoco and in the Valley of Mexico. When the Spaniards arrived, the Aztec Empire reached much of Mesoamerica, touching both the Gulf of Mexico and the Pacific Ocean. The population of Tenochtitlan in 1519 has been estimated as between 150,000 and 200,000; the population of London at that time was approximately 50,000; Paris was approximately 300,000.