Irene

She's a Spanish noblewoman visiting Rome invited by Cardinal Silvio Passerini. She's staying in Arte's old house.
In actuality, Lady Irene is ~!no more than a façade created for the sake of protecting the Castilian Infanta, Catarina, who has arrived in Florence for down-time before marrying her betrothed.!~
Arte finds her to be quite puzzling to read: Irene’s overwhelming aura confuses Arte and her piercing gaze perplexes her. It is for this reason, however, that Arte is determined to figure her out and paint a portrait worthy of Lady Irene. Arte manages to succeed by opening her heart to Lady Irene, who is promptly encouraged to do the same:
~!Daughter to Juana the Mad, Catarina values love and being loved above anything else. She does not consider Arte’s being a painter abnormal or peculiar, just like how she does not think of herself or her mother as “weird” or “strange” for having remained imprisoned for ten years of Irene’s lifetime (and, to the extent of Irene, actually liking said imprisonment.)!~ The fire of passion and determination burning in her eyes while she speaks of said circumstances become the key to Arte’s performance excelling and her portrait being deemed worthy of Lady Irene.