Four years after deciphering Palmyrene, the first ancient script to be deciphered, in 1758 French writer, numismatist and linguist Abbé Jean-Jacques Barthélemy deciphered Phoenician on the basis of blingual Phoenician and Hebrew inscriptions found in Malta and two bilingual Phoenician and Hebrew inscriptions found in Cyprus by Richard Pococke. Bathélemy confirmed his reading with bilingual coins of from Tyre and Sidon, and a set of Sicilian-Punic tetradrachms.
Barthélemy published his discovery in "Réflexions sur quelques monuments phéniciens, et sur les alphabets qui en résultent," Memoires de l'Académie des Inscriptions et Belles Lettres 30 (1764) 405-26. In this paper Barthélemy postulated four rules of decipherment which withstood the test of time.
My copy of Barthélemy's paper is a preprint paginated 1-23, with 5 plates. According on a note published in the margin of p. 1, Barthélemy read his report to the Académie des Inscriptions on April 12, 1758. It was not formally published until six years later, and from a setting of type different from my copy. The first of his plates reproduced the Malta inscriptions, the second reproduced recto and verso of 10 bilingual coins, the third reproduced the inscriptions found on Cyprus, and his fourth plate set out his understanding of the Phoenician alphabet. A fifth plate in my copy reproduces an inscription on a pitcher.
Daniels & Bright, The World's Writing Systems (1996) 144, 155.