The way that melodies and motifs are used adds so much depth to the piece.
Listen carefully to Cesare's part of "Akogare no Dante".
While the musical does pack a lot of detail and nuance in regards to the historical political situation into the spoken and sung dialogue of the play, there's even more to be found in the music itself.
Cesare's first solo and "I Want" Song, "Cesare" is through-composed (it doesn't repeat themes within that song). In the second section of it, he sings of the proper teachings and word of God that the church should be focused on conveying, and the section ends with the line, "To pray, and just to pray, should be enough, but...", after which he dramatically throws off his cape and continues into the darker and grittier third section, about the rotting Babylon of greed that the church has become in reality. That second section shares a tune with Lorenzo de'Medici's "Renaissance", in which Lorenzo describes the humanistic opportunity his rule has brought to Florence. "As humanity walks into the future, and the eras continue to change, this Renaissance could be the era when humanity gains wings." Like the church, however, the reality under the surface is very different.
Rodrigo's song in the beginning of act 2 contrasts him with Cesare, whose song in the beginning of act 1 couldn't be more different. But if you listen closely, the melodies are so related that they're practically the same song. And blocking-wise, Cesare takes a direct path down the stairs once, while Rodrigo struts back and forth up and down them and flirts with the audience, and his song includes a dance break (it's Miguel and the other Spain students who dance, not Rodrigo).
In the end of "Cesare", the stage begins to turn when Cesare sings "Someone has to — yes — I have to!" In Rodrigo's song, it begins to turn on the words "We, the Borgias" (also a first-person pronoun). In context, Cesare is talking about how he wants to reform the church and create a true Kingdom of God. That line in Rodrigo's song is about how the family is renowned not just a priests but also as soldiers, contrasting the worldly Rodrigo with the more idealistic Cesare.
Both songs end with a more quiet stanza looking forward to the future — Rodrigo's, to the family expanding their power even further; Cesare's, to the rotten fruit of the world falling to the ground, and a new world sprouting from its seeds.
The beginning of Giovanni's solo part in his graduation scene uses the tune of Dante's Paradiso song ("Tengoku ni mukaerareta, hitobito ga suwaru..."). According to Squadra Verde's Giovanni, Kazama Yujiro, this is done to show that Giovanni is looking to Dante as a great Florentine of the past, and wanting to live up to that responsibility to bring glory to Florence as Dante did.
, he sings of the proper teachings and word of God that the church should be focused on conveying, and the section ends with the line, "To pray, and just to pray, should be enough, but...", after which he dramatically throws off his cape and continues into the darker and grittier third section, about the rotting Babylon of greed that the church has become in reality. That second section shares a tune with Lorenzo de'Medici's "Renaissance"