There have always been great uncertainties about the dating of the four mosaics at a lower level, in stationes 52 (hunter), 53 (Nereid), 57 (Diana) and 58 (stuppatores restiones). In 1930 Blake tended to date to the second century (Blake 1930, 101, 123):
"This pavement seems to correspond to the travertine base of the columns. The last two subjects [hunter, Nereid] are quite different from anything which we have as yet encountered in the first century after Christ. Inasmuch as these mosaics are very evidently the result of private initiative, they might have been laid at any time after their level was determined by the reconstruction of Claudius until the new level was established under Commodus. All four are not necessarily of the same date".
"Representations of the hunt, though common in many huge wall paintings in Pompeii, were not entrusted to mosaic until the second century after Christ. In fact [... with two exceptions ...] I recall no other animal pictures belonging to our period [the first century]. The delineation of fantastic animals, whether of the land or of the sea, is almost equally rare. [...] Fantastic animals of the sea are represented only by the hippocampus. [... three instances from Pompeii ...] The Piazzale delle Corporazioni at Ostia furnishes a fourth [Nereid] which may, or may not, belong to the first century AD. [... a few instances of the human figure in Italy only, in Pompeii ...] In the rest of Italy, instances of the representation of the human figure in mosaic are equally rare during this period. We have already called attention to one from the Claudian level of the Piazzale delle Corporazioni at Ostia [hunter]".In 1961 Becatti proposes dates ranging from the first half of the first century (but misreading Blake) to the second half of the second century AD. In 1973 and 1979 new dates were proposed by Clarke in his extensive study of Roman black-and white mosaics (full text). I summarized the evidence for the oldest mosaics in a table:
Information Hunter and bull (52) Nereid on sea-horse (53) Diana and deer (57) Stuppatores restiones (58) Calza 1915 Stratigraphy
Architecture(Augustus-?) Claudius --- (Augustus-?) Claudius (Augustus-?) Claudius Becatti 1961
+ photosStylistic ca. 150 AD, covered by mosaic with ship of final raising ca. 138-200 AD ca. 150 AD 1-50 AD (misreading Blake) Tesserae Size of tesserae 0.01 Size of tesserae 0.01 Size of tesserae 0.015 Size of tesserae 0.015 Panels Panel 1.58 x 2.29, centered between columns Panel 1.93 x 2.29, centered between columns Panel ca. 2.95 x 2.40, not centered between columns Panel 1.90 x 2.00, centered between columns Frames Frame of black lines and wicker-work Frame of black lines Frame of black line and very thick band Frame of black lines Around frames Around frame white diagonal lines Around frame white diagonal lines Around frame white diagonal lines --- Clarke 1973 and 1979 Stylistic ca. 150 AD ca. 160-180 AD ca. 160-180 AD --- Pohl 1978 Stratigraphy
Architectureca. 100 AD (phase IIb) ca. 100 AD (phase IIb) ca. 100 AD (phase IIb) ca. 100 AD (phase IIb) Columns --- Tuscan decoration of 53south changed to Ionic (also 42south and 44south) (phase IIb1) --- --- Plinths --- Mosaic above travertine plinth, touching shaft of column (phase IIb2) --- Mosaic above travertine plinth, touching shaft of column (phase IIb2) Observations 2019 Plinths No travertine plinths visible, no brick plinths present; mosaic next to columns not preserved No travertine plinths visible, no brick plinths present; black tesserae imitate curved plinths set against columns Square travertine plinths visible, no brick plinths present; travertine plinth standing on top of mosaic; mosaic at Claudian level No plinths depicted on drawing Notizie degli Scavi Masonry Dividing wall with 53 standing on lower level and rising above upper level Dividing wall with 52 standing on lower level and rising above upper level; followed by black mosaic band on lower level --- --- The oldest mosaic is that of Diana in statio 57, and it can be dated pretty accurately. It rests on the Claudian level. It was laid when there were no brick columns in the current position: the mosaic is off-centre and the travertine base of the brick column in the north-east corner of the back room is standing on top of the black edge of the mosaic. Strange to say, this does not seem to have been noticed before.[1] An implication is, that there were no columns in the Augustan phase on the current spots.
These observations create two major problems however. First of all, the stylistic datings for the mosaic of Diana are much later: ca. 150-180 AD. We could try to solve this problem by thinking of a replacing of a Claudian panel in the second half of the second century. There is however not a single indication of such an action. Also, in that case the mosaic would have been placed more in the centre of the room, which was by now flanked by brick columns. Secondly, it is hard to believe that such a major change of plan took place in the Claudian period: an original lay-out without brick columns, finalised by the laying of mosaics, followed immediately by a new lay-out with brick columns. A more natural solution is that the brick columns do not belong to the reign of Claudius, as generally believed so far. That the foundations of the columns were poured later is suggested several times by Pohl. We may then think of the period of Domitianus, when the temple was built, and when the entire outer wall of the east porticus was re-erected in brick, together with rooms to the east. In that case there would have been interventions involving the roof of the porticus on all sides of the square.
The other three mosaics are at a slightly higher level (+0.10 to +0.15), above the travertine plinths of the brick columns, set against plaster of the Ionic order (replacing plaster of the Tuscan order), and below the Hadrianic level. No coins or datable ceramics were found in the layer they are resting on. This raises three questions. What prompted the slight raising of the level, involving the covering of the lower part of the columns? When was the Tuscan order replaced by the Attic-Ionic order? How are the mosaics to be dated? It should be noted that we do not know what ancient layers were on top of the mosaics in stationes 53 (Nereid) and 58 (stuppatores restiones). We only know that a mosaic from the period ca. 190-210 AD was found on top of the hunter in statio 52.
The most natural solution for the slight raising is that the travertine plinths were covered because they were considered to be "old fashioned" and conflicting with a new situation. This would take us to the Hadrianic phase, when new, fake brick plinths were added. The proposed stylistic dates for the mosaics are somewhat later, ca. 138-200 AD. The rather harsh bumping into the column of the mosaic in statio 53 seems to have been compensated for by adding a black, round mosaic plinth instead of a brick plinth (this cannot be verified in stationes 52 and 58). The change to the Ionic order would thus have taken place somewhere in the period Domitianus - Hadrianus, to be followed by the laying of mosaics at a somewhat higher level (Pohl phase IIb), simultaneous with Hadrianic floors at a still higher level (Pohl phase II). To be on the safe side it seems best to date the three mosaics to the Trajanic-Hadrianic period.
It is becoming more and more apparent that (mirabile dictu) the porticos were never entirely at the same level. This is also suggested by a wall between statio 52 (with the hunter, covered later by a mosaic of a ship with oil amphorae) and statio 53 (with the depiction of a Nereid). In statio 53 we can see that the wall rests on the mosaic and is followed by a black band (the mosaic along the wall in statio 52 is lost): the wall rises considerably above the final level.
In this respect attention should also be paid to the presence or absence of Hadrianic fake, brick plinths. The plans of Vaglieri and Gismondi show many columns with and without plinths. The plans however are contradictory and do not coincide with the current situation. Most of the columns in the south part of the west porticus (51south - 61south) do not have brick plinths. Around the southern central column of statio 54 is half a brick plinth. The situation around the column between stationes 54 and 53 is complex. Pohl notes that here a brick plinth has not been preserved and was not restored in modern times. However, she interprets a fragment of stone next to the south side as a support of a brick plinth. It is almost as if the mosaic brick "plinth" on the north side complements a (disappeared) part of a slightly higher brick plinth on the other side.
Stylistically Becatti assigns the mosaics of the upper level to the decade 190-200 AD, with the exception of stationes 27-28 (Alexandria), which he places around 150 AD. For the latter mosaic Clarke suggests ca. 170 AD. The remaining mosaics are assigned by him to ca. 190 AD (stationes 10 and 11) and 200-210 AD.[2]
At the end of the fourth century the porticos, with neglected and by now much damaged mosaics, had to be prepared for an audience watching performances of jugglers, gladiators et cetera on the square. For the future of the mosaics, the restorers had three choices: completely remove and replace them; restore the original as far as possible; fill the gaps in such a way that restoration would be obvious. Removal was apparently not an option. Restoration to the original state would have led to an anachronistic situation. Therefore the latter option was chosen: respect was shown towards the depictions that were by now two centuries old (and in a way still current, because of the ongoing activities in Portus); simultaneously the nature of the restorations made it clear that the mosaics were something of the past.
Fragmentary grave stele showing mosaicists preparing tesserae. Probably early fourth century AD.
Museo Ostiense. Photo: Tonino Menghi.
(1) Finelli already notes that the mosaic of Diana is the oldest one. Discussing the excavations of the lower level of statio 53 he says (GdS 1914, 18 (January 9-24)): "Questo mosaico si trova alla stessa livello di quello degli stuppatores e cordari e perciò più alto delle basi delle colonne e più alto ancora del mosaico di Diana." Not much later he adds (GdS 1914, 34 (February 2-7)): "... presto i saggi saranno allargati, e dove non sarà possibile allargare, lo scavo entrerà sotto a forma di grotte per vedere se ve ne sono degli altri più antichi che possono andara con quella della Diana, che finora sarebbe il più antico mosaico del portico dietro al teatro e con quelli col Torero, Nereide e con quelli così detto degli stuppatori."
(2) For 200-210 Clarke mentions explicitly stationes 5, 14, 15, 18, 21, 23, 25, 32, 45, 46, 47, 51, 52.
