In The Thorn Birds (1977) McCullough examined the love relationship between Meggie and Father Ralph de Bricassart, the ambitious priest. Theirs was an unequal relationship. While Meggie loved Ralph totally and unconditionally, Ralph loved Meggie, but because of his ambitions in the church, he would never fully commit himself to her. In The First Man in Rome, McCullough explores the love relationship between Julilla and Sulla which, like Meggie and Ralph's, is a source of much pain and unhappiness.

McCullough also explored ambition as a motivating force in The Thorn Birds. Father Ralph de Bricassart was an ambitious priest who aspired to rise to the top in the church's hierarchy.

While his methods were not as ruthless as Sulla's, his success was realized at the expense of his and especially Meggie's personal happiness.

The First Man in Rome is the first in a projected series of five...