Who were the Duke and Duchess of Ferrara?

So, who were the Duke and Duchess of Ferrara, so important that Lorenzo would write to each, individually, immediately after the death of his beloved mother Lucrezia?  And where is Ferrara?

Ferrera, in the province of Emilia-Romagna, today is a one hour train ride north from Florence.  It's a well preserved walled medieval city, with many 15th and 16th century palazzos, as well as a Romanesque cathedral (pictured above).

Back in Lorenzo's day, the Duke of Ferrara, Ercole I d'Este, was an important ally during the Pazzi War (the aftermath to the Conspiracy).

"The Duchess of Ferrara, Eleanora d'Aragona, has a special place in the history of patronage in the Renaissance period because of the notable amount, quality, and innovative subject matter of the works she sponsored.  She came to Ferrara from Naples in 1473 at the time of her marriage to the Ferrarese ruler, Duke Ercole I d'Este, and became an important sponsor of art and architecture in the city of the Este family until her death in 1493.  Most other wives of courtly rulers in the fifteenth century were less active in their art patronage.  Eleanora was notable for the scale and diversity of the artworks produced specifically for her during her reign, works that included significant building projects in the city of Ferrara, fine illuminated manuscripts, mural painting, and pictures on panel."  (from Joseph Manca's article on "Isabella's Mother:  Aspects of the Art Patronage of Eleanora d'Aragona, Duchess of Ferrara, in The Journal of the History of Art)