unknown. In Attic Greek, the Etruscans were known as Tyrrhenians (, Tyrrhēnoi, earlier Tyrsēnoi), from which the Romans derived the names Tyrrhēnī, Tyrrhēnia (Etruria), and Mare Tyrrhēnum (Tyrrhenian Sea), prompting some to associate them with the Teresh (one of the Sea Peoples named by the Egyptians). The ancient Romans referred to the Etruscans as the Tuscī or Etruscī (singular Tuscus). Their Roman name is the origin of the terms "Toscana", which refers to their heartland, and "Etruria", which can refer to their wider region. The term Tusci is thought by linguists to have been the Umbrian word for "Etruscan", based on an inscription on an ancient bronze tablet from a nearby region. The inscription contains the phrase turskum ... nomen, literally "the Tuscan name". Based on a knowledge of Umbrian grammar, linguists can infer that the base form of the word turskum is *Tursci, which would, through metathesis and a word-initial epenthesis, be likely to lead to the form, E-trus-ci. As for the original meaning of the root, *Turs-, a widely cited hypothesis is that it, like the word Latin turris, means "tower", and comes from the Greek word for tower: . On this hypothesis, the Tusci were called the "people who build towers" or "the tower builders". This proposed etymology is made the more plausible because the Etruscans preferred to build their towns on high precipices reinforced by walls. Alternatively, Giuliano and Larissa Bonfante have speculated that Etruscan houses may have seemed like towers to the simple Latins. The proposed etymology has a long history, Dionysius of Halicarnassus having observed in the first century B. C., "[T]here is no reason that the Greeks should not have called [the Etruscans] by this name, both from their living in towers and from the name of one of their rulers." In his recent Etymological Dictionary of Greek, Robert Beekes claims the Greek word is a "loanword from a Mediterranean language," a hypothesis that goes back to an article by Paul Kretschmer in Glotta from 1934. Origins Ancient sources Literary and historical texts in the Etruscan language have not survived, and the language itself is only partially understood by modern scholars. This makes modern understanding of their society and culture heavily dependent on much later and generally disapproving Roman and Greek sources. These ancient writers differed in their theories about the origin of the Etruscan people. Some suggested they were Pelasgians who had