While ancient sources have been interpreted in a variety of ways, one theory identifies the Tyrsenians with the Etruscans, and therefore with the Rhaetian and Lemnian cultures, whose languages have been grouped together as the Tyrsenian languages, based on strong similarities in their written languages.
The names are believed to be exonyms, only known to have been used by authors of Ancient Greek, though their origin is uncertain and apparently not Greek. They have been connected to tursis, also a "Mediterranean" loan into Greek, meaning "tower". Direct connections with Tusci, the Latin exonym for the Etruscans, from Turs-ci, have also been attempted. While it has been hypothesized by the French linguist Françoise Bader that Tyrsenoi/Tyrrhenoi derives from the very ancient Indo-European root *trh indicating "to cross". 
And Circe the daughter of Helios, Hyperion's son, loved steadfast Odysseus and bore Agrius and Latinus who was faultless and strong; also she brought forth Telegonus by the will of golden Aphrodite. And they ruled over the famous Tyrsenians, very far off in a recess of the holy islands.
The Homeric hymn to Dionysus has Tyrsenian pirates seizing Dionysus:
Presently there came swiftly over the sparkling sea
Tyrsenian pirates on a well-decked ship – a miserable doom led them on.
The Tyrrhenians are referred to as pirates by Ephorus of Cyme as reported by Strabo. The pirating actions of the Tyrrhenians would not have allowed the Greeks to found their colonies in Sicily before the VIII century BC.
According to Ephorus these were the earliest Greek cities to be founded in Sicily, that is, in the tenth generation after the Trojan war; for before that time men were so afraid of the bands of Tyrrhenian pirates and the savagery of the barbarians in this region that they would not so much as sail thither for trafficking.
In the 6th and 5th centuries BC, the name referred specifically to the Etruscans for whom the Tyrrhenian Sea is named, according to Strabo. In Pindar, the Tyrsanoi appear allied with the Carthaginians as a threat to Magna Graecia:
I entreat you, son of Cronus,
grant that the battle-shouts of the Carthaginians and Tyrrhenians stay quietly at home,
now that they have seen their arrogance bring lamentation to their ships off Cumae.
The name becomes increasingly associated with the generic Pelasgians. Herodotus places them in Crestonia in Thrace, as neighbours of the Pelasgians. Similarly, Thucydides mentions them together with the Pelasgians and associates them with Lemnian pirates and with the pre-Greek population of Attica.
Lemnos remained relatively free of Greek influence until Hellenistic times, and the Lemnos stele of the 6th century BC was inscribed with a language very similar to Etruscan, which has led to the postulation of a Tyrrhenian language family of Etruscan, Lemnian and Raetic.
There is thus evidence that there was indeed at least a linguistic relationship between the Lemnians and the Etruscans. The circumstances of this are disputed; most scholars would ascribe Aegean Tyrrhenians to the Etruscan expansion from the 8th to the 6th centuries, putting the homeland of the Etruscans in Italy and the Alps, particularly because of their relation to the Alpine Rhaetian population. Another hypothesis connecting the Tyrrhenians and the Etruscans posits that the Etruscans derive at least partially from a 12th century BC invasion from the Aegean and Anatolia imposing itself over the Villanovan culture, with some scholars claiming a relationship or at least evidence of close contact between the Anatolian languages and the Etruscan language and adherents of the latter school of thought point to the legend of Lydian origin of the Etruscans referred to by Herodotus and Livy's statement that the Rhaetians were Etruscans driven into the mountains by the invading Gauls. Critics of the theory point to the very scanty evidence of a linguistic relationship of Etruscan with Anatolian and to Dionysius of Halicarnassus, who decidedly argues against an Etruscan-Lydian relationship. Furthermore, there is no archaeological evidence from material culture of such a cultural shift and of an eastern origins of the Etruscans, in modern times, all the evidence gathered so far by etruscologists points to an indigenous origin of the Etruscans. Just as the archaeological evidence is against the idea that the Rhaetians are descended from the Etruscans who fled from northern Italy because of the Gallic invasions, as the Rhaetians are archaeologically attested in their Alpine sites long before.
Possible connection with Sea Peoples
- "Already in the 1840s Egyptologists had debated the identity of the "northerners, coming from all lands," who assisted the Libyan King Meryre in his attack upon Merneptah. Some scholars believed that Meryre's auxiliaries were merely his neighbors on the Libyan coast, while others identified them as Indo-Europeans from north of the Caucasus.
It was one of Maspero's most illustrious predecessors, Emmanuel de Rougé, who proposed that the names reflected the lands of the northern Mediterranean: the Lukka, Ekwesh, Tursha, Shekelesh, and Shardana were men from Lydia, Achaea, Tyrsenia (western Italy), Sicily, and Sardinia." De Rougé and others regarded Meryre's auxiliaries – these "peoples de la mer Méditerranée" – as mercenary bands, since the Sardinians, at least, were known to have served as mercenaries already in the early years of Ramesses the Great. Thus the only "migration" that the Karnak Inscription seemed to suggest was an attempted encroachment by Libyans upon neighboring territory." — R. Drews (1995, p.54)
- Liddell, Henry George; Scott, Robert. "Τυρσηνός". A Greek-English Lexicon. Perseus. Tufts U.
- Heubeck, Alfred (1961). Praegraeca: sprachliche Untersuchungen zum vorgriechisch-indogermanischen Substrat. Erlangen. pp. 65ff.
- Françoise Bader (2003), Une traversée menée à terme: noms de conquérant i.e. en étrusque (Pélasges, Tyrrhènes, Tusci, Etrusci, Tarkon, Tarquin), pp 33-49, in Linguistica è storia. Sprachwissenschaft ist Geschichte. Scritti in onore di Carlo De Simone. Festschrift fùr Carlo De Simone, a cura di Paolo Poccetti, Simona Marchesini, Pisa 2003.
- Hesiod, Theogony 1015.
- Hesiod, Theogony, 1015.
- Homeric hymn to Dionysus, verse 7ff.
- Ephorus of Cyme in Strabo, Geography, VI, 2, 2
- Strabo, 5.2.2.
- Pindar, Pythian Odes, 1.72
- Sophocles, Inachus, fr. 256
- Herodotus, Histories, 1.57
- Thucydides, 4.106
- Herodotus, Histories, 1.94
- Wallace, Rex E. (2018), "Lemnian language", Oxford Research Encyclopedia of Classics, Oxford University Press, doi:10.1093/acrefore/9780199381135.013.8222, ISBN 978-0-19-938113-5
- Turfa, Jean MacIntosh. "The Etruscans". In Farney, Gary D.; Bradley, Gary (eds.). The Peoples of Ancient Italy. Berlin: De Gruyter. pp. 637–672. doi:10.1515/9781614513001. ISBN 978-1-61451-520-3.
- De Grummond, Nancy T. (2014). "Ethnicity and the Etruscans". In McInerney, Jeremy (ed.). A Companion to Ethnicity in the Ancient Mediterranean. Chichester, UK: John Wiley & Sons, Inc. pp. 405–422. doi:10.1002/9781118834312. ISBN 9781444337341.
- Shipley, Lucy (2017). "Where is home?". The Etruscans: Lost Civilizations. London: Reaktion Books. pp. 28–46. ISBN 9781780238623.
- Drews, Robert (1995). The End of the Bronze Age: Changes in warfare and the catastrophe ca. 1200 B.C. Princeton University Press. p. 54.