Before the Spanish conquest, the Pipil people established their capital, Cuzcatlan, near the current location of San Salvador. Not much is known about Cuzcatlan, as it was abandoned by its inhabitants in an effort to avoid Spanish rule. Under the orders of conquistador Pedro de Alvarado, his associates Gonzalo de Alvarado and Diego de Holguín occupied the empty settlement and began to develop it. Diego de Holguín became the first mayor of San Salvador after the town was founded on 1 April 1525. The town changed location twice, in 1528 and 1545. Originally established in what is now the archeological site of Ciudad Vieja, north of the present-day city, it was moved to the ''Valle de Las Hamacas'', so named for the intense seismic activity that characterizes it. The new site was chosen because it had more space and more fertile land, thanks to the Acelhuate river. The population of the city remained relatively small until the early 20th century.