[3][4] Upon his arrival, López de Haro began to express his overall dislike with the conditions of the Colony of Puerto Rico at that time and convened a Synod.
In his final years as Bishop, López de Haro began visiting annexed regions of the diocese in what is now Venezuela.
Of the most notable are King Philip IV, and Juan Diez de la Calle, a clerk of the secretary of New Spain of the Council of the Indies (in Madrid).
In his letters to King Philip were descriptions of the state of the diocese on both the Island of Puerto Rico, City of San Juan Bautista, and annexes.
[7] López de Haro has also written some of the first recordings of Taíno folk tales[8] and his writings are the only known historical description of Puerto Rico in the mid-seventeenth century.