Yes, there is still controversy about the date.
Why 24 August?
The year of the eruption is reliably pinned to 79 AD. This is not by "literature", but by epigraphic primary sources - notably a letter from Pliny the Younger to Tacitus. This is further confirmed by references to the eruption by other, contemporary, Roman writers including Cassius Dio.
What has been questioned is the date. The Wikipedia article you mention actually explains quite clearly how we come by the date of 24 August. It is from the letter from Pliny the Younger to Tacitus:
where it appears as "nonum kal. Septembres". This seems to be an abbreviation of a standard date, to be interpreted as "the ninth day before the Kalends of September", which in the Julian calendar, in general use by then, would have been eight days before September 1, that is August 24
However, we do not have the original letter. This raises the possibility of errors in transcription by later copyists. Indeed, the surviving manuscripts are not all consistent in regard to the date of the eruption.
The most recent paper that I am aware of that challenges the traditionally accepted date was published in 2007, and boasts the rather catchy-title, The 79 AD eruption of Somma: The relationship between the date of the eruption and the southeast tephra dispersion by Rolandi et al.
This pulls together several strands of evidence - including the coin that you mentioned (which records the fifteenth imperial acclamation of the
emperor Titus) - to argue for a later date in the Autumn of 79 AD.
Evidence suggesting a later date
Firstly, it is worth noting that, in addition to the inconsistencies in the manuscript copies of Pliny's letter noted above, other documentary sources do not support the August date for the eruption. According to the annals of Cassius Dio, the eruption occurred in the Autumn of 79 AD.
The physical evidence recovered by archaeologists is also problematic.
As far back as 1797, the archaeologist Carlo Maria Rosini recovered traces of pomegranate, chestnut, dried figs, raisin and other goods which he interpreted as indicating an autumn date for the eruption. In the late nineteenth century, Ruggiero confirmed the presence of Autumnal fruits in the archaeological record, and also identified residue from the grape harvest, which would also be expected to occur in Autumn.
These results have been confirmed in more recent excavations in 1990 [Pappalardo, 1990] and 2001 [Borgongino & Stefani, 2001].
The coin you mentioned in the question was found during a 2006 excavation in the "House of the Gold Bracelet" in Pompeii. It records the fifteenth imperial acclamation of the emperor Titus. The obverse reads:
IMP TITUS CAES VESPASIAN AVG PM
Imperator Titus Caesar Vespasianus Augustus pontifex maximus
and on reverse face it reads:
TR P VIIII IMP XV COS VII PP
tribunicia potestate VIIII, imperator XV, consul VII, pater patriae.
These events were recorded by Cassius Dio, and that, combined with other epigraphic evidence (discussed in the paper by Rolandi et al cited above), suggest that the coin should not have been struck until after 8 September 79 AD.
The material ejected by Vesuvius ("tephra") was dispersed in a southeasterly direction during the eruption in 79 AD. Rolandi et al compared that with other eruptions of the volcano over the last 25 thousand years, and found that the distribution does not match what would be expected given the known high-altitude winds in the region in late summer. On its own, this could be simply the result of a weather anomaly. However, when combined with the other physical evidence it suggests a later date for the eruption.
Since all the available physical evidence suggest an Autumnal date for the eruption, the authors conclude that the date in the surviving Pliny manuscript cannot be correct. They go on to say that:
it is plausible that the eruption happened 24 October, i.e. nonum kalendas novembres — a reading that does not appear completely in the codex, but unifies the two most frequent versions: “non(um) kal” and “kal novem(bres),” rather than introduce the name of Decembres that does not appear, as stated, in any source.
Most historians and archaeologists of my acquaintance still refer to 24 August 79 AD as the traditional date for the eruption of Mount Vesuvius. While we are aware of the questions raised by the physical evidence, and the suggested alternative reading of Pliny discussed above, there remains, as yet, no consensus.
- Borgongino, M., Stefani, G: Intorno alla data dell'eruzione del 79
d.C. Rivista di Studi Pompeiani XII–XIII, 177–215, 2001
- Pappalardo, U: L'eruzione pliniana del Vesuvio nel 79 d.C:
Ercolano. PACT 25, 1990
- Rolandi, G, Paone, A, Di Lascio, M, and Stefani, G: The 79 AD
eruption of Somma: The relationship between the date of the eruption
and the southeast tephra dispersion, Journal of Vulcanology and
Geothermal Research vol 169 (2007) 87–98.
- Rosini, C.M: Dissertationes isagogicae ad Herculanensium voluminum
explanationem: pars prima, 1797
- Ruggiero, M: Del mese e del giorno dell'eruzione in Pompei e la
regione sotterrata dal Vesuvio, Napoli, 1879