What was the title of Tibullus' first book of elegies?

The title of Tibullus' first book of elegies is "Delia." This collection is notable for its personal and intimate themes, focusing on love and the poet's feelings for his beloved Delia. Tibullus is recognized for his contribution to the genre of elegy, where he often blends motifs of love with pastoral imagery and existential reflections.

The significance of "Delia" lies in its pioneering role in establishing the themes of elegiac poetry in Roman literature, distinct from the works of other poets like Propertius and Ovid, who focused on different aspects of love and relationships. Tibullus’ portrayal of love is deeply emotional, emphasizing tenderness and vulnerability, which helps define the Roman elegiac tradition.

Other options in the question refer to works by different poets or themes. "Amores" is associated with Ovid, who wrote a collection of love poems. "Nemesis" typically refers to themes related to retribution and justice rather than love poetry. "Elegiae" generally denotes elegies but does not specify that it is Tibullus' first book. Thus, "Delia" stands as the identifiable title of his first significant work in the elegiac genre.