I think the cover reads as follows:
A mi Senor el Com[endado]r Ysasaga
Factor de la Casa de la Contratacyon
En[?] Sevylla
To my Lord Commander Ysasaga / Factor of the House of Trade / In Seville
The “Casa de la Contratación” or the House of Trade in Seville (1503-1790), later known as the Supreme Council of the Indies, was founded by Queen Isabella in 1503 to manage and control all trading with the East Indies. All goods had to pass through the institution and pay the “quinto,” a 20% tax, to the Crown. On August 20, 1509, Ochoa de Isásaga was named the “Comendador” or chief of the Casa de la Contratación.