The objective of this work is to delve into the authors who participated in the so called epistolary correspondence between Gongora's and Lope de Vega's circles. To do this, a total of five testimonies are studied, disseminated between 1613 and 1615, involving, at least three authors: Antonio de las Infantas y Mendoza, Gongora himself and Lope de Vega or someone close to him. Among other things, the study of these authors provides new data about the human and literary profiles of Antonio de las Infantas. Likewise, light is shed on the discussion about whether Gongora's letters are authentic or not and eventually, interesting and innovative relationships are established between the author or authors of the anonymous letters and the author of the apocryphal Quijote.