The Unraveling of Julia by Lisa Scottoline

Lately, Julia Pritzker is beginning to think she’s cursed. She’s lost her adoptive parents, then her husband is murdered. When she realizes that her horoscope essentially foretold his death, she begins to spiral. She fears her fate is written in the stars, not held in her own hands.

Then a letter arrives out of the blue, informing her that she has inherited a Tuscan villa and vineyard —but her benefactor is a total stranger named Emilia Rossi. Julia has no information about her biological family, so she wonders if Rossi could be a blood relative. Bewildered, she heads to Tuscany for answers.
There, Julia is horrified to discover that Rossi was a paranoid recluse, who believed herself to be a descendent of Duchess Caterina Sforza, a legendary Renaissance ruler. Stunned by her uncanny resemblance to Rossi, and even to Caterina, Julia is further unnerved when she unearths eerie parallels between them, including an obsession with astrology.
Before long, Julia suspects she’s being followed, and strange things begin to happen. Not even a chance meeting with a handsome Florentine can ease her troubled mind. When events turn deadly, Julia’s harrowing struggle becomes a search for her identity, a race to save her sanity, and ultimately, a question of her very survival.