tribute to the Spanish in the form of valuable products such as cacao, cotton, salt and vanilla, with an emphasis on cacao. Northern lowlands The Contact Period in Guatemala's northern Petén lowlands lasted from 1525 through to 1700. Superior Spanish weaponry and the use of cavalry, although decisive in the northern Yucatán, were ill-suited to warfare in the dense forests of lowland Guatemala. Cortés in Petén In 1525, after the Spanish conquest of the Aztec Empire, Hernán Cortés led an expedition to Honduras over land, cutting across the Itza kingdom in what is now the northern Petén Department of Guatemala. His aim was to subdue the rebellious Cristóbal de Olid, whom he had sent to conquer Honduras, but Cristóbal de Olid had set himself up independently on his arrival in that territory. Cortés had 140 Spanish soldiers, 93 of them mounted, 3,000 Mexican warriors, 150 horses, a herd of pigs, artillery, munitions and other supplies. He also had with him 600 Chontal Maya carriers from Acalan. They arrived at the north shore of Lake Petén Itzá on 13 March 1525. Cortés accepted an invitation from Aj Kan Ekʼ, the king of the Itza, to visit Nojpetén (also known as Tayasal), and crossed to the Maya city with 20 Spanish soldiers while the rest of his army continued around the lake to meet him on the south shore. On his departure from Nojpetén, Cortés left behind a cross and a lame horse. The Spanish did not officially contact the Itza again until the arrival of Franciscan priests in 1618, when Cortés' cross was said to still be standing at Nojpetén. From the lake, Cortés continued south along the western slopes of the Maya Mountains, a particularly arduous journey that took 12 days to cover , during which he lost more than two-thirds of his horses. When he came to a river swollen with the constant torrential rains that had been falling during the expedition, Cortés turned upstream to the Gracias a Dios rapids, which took two days to cross and cost him more horses. On 15 April 1525 the expedition arrived at the Maya village of Tenciz. With local guides they headed into the hills north of Lake Izabal, where their guides abandoned them to their fate. The expedition became lost in the hills and came close to starvation before they captured a Maya boy who led them out to safety.