What is Etrusca in the novel, The Early History of Rome: Books I-V?

At it's peak, the area known as Etrusca reached from the Alps to the edge of Italy. This was a pre-Roman culture. They had metal working and were expansive and pro-active about trading with others. During the book no one mentions the superior metals science and technology but everyone admits that they are superior at augery and all manner of spiritual and religious matters.