Metropolitan museum of art
The typical Greek muscled thorax of Late Classical and Hellenistic age. This one belongs to the 4th century BC. Following the battle of Leuctra (371 BC) the Spartan and the other hoplite armies introduced its use more  imperatively  (Metropolitan Museum of Art, photo by ‘Emiliano Zapata’).

.

By  Periklis  Deligiannis
.
The Geometric bell-type cuirass was the main type of armor of the Greek hoplite during the Archaic age (700-479 BC) and was the most popular among the Spartans of this era. At the end of the 6th century BC, the hoplites bearing bronze armour adapted to this a row of metal, leather or linen protective strips (called pteruges, i.e. wings) and later a double row, thus complementing the protection of the lower part of their body. At the same time, there was a massive shift of preference of the Greek hoplites to the linothorax (λινοθώραξ), that is the linen cuirass, and secondarily to the leather one. In the 5th century BC the linen cuirass largely supplanted the leather one and limited the use of the metal armour, thereby becoming the most popular Greek thorax. The linen and leather thoraxes were not used to any significant extent by the Spartans, however it seems that they were the prevailing ones in the other categories of Lacedaemonians (the other free inhabitants of the Spartan/Lacedaemonian state, except the Spartans). The Greek cuirasses made of flexible materials could be partially covered with bronze scales or plates that were stitched to the linen or leather base. These variations do not seem to be ever used by the Spartan or generally the Lacedaemonian hoplites.

Following the Greco-Persian Wars, the engraved depiction of the male anatomy of the Archaic bell-type bronze armor became sculpted, evolving to the new muscled or anatomical type. At the same time, its bell-type end was extended gradually downwards covering the abdomen and groins, thus substituting the Archaic protective bronze plate of this area, called ‘mitra(μίτρα). In the final form of the anatomical armor, the male muscles are depicted accurately on its surface. Simultaneously, the protection of the lower part of the torso was achieved by two rows of leather or linen strips (but not longer brazen ones). The muscled bronze cuirass was the one that prevailed overwhelmingly among the Spartan omoioi (full citizens, the elite force of the Spartan/Lacedaemonian army). It was an expensive armor, but it was the dominant among the Spartan hoplites because essentially the only luxury that they were allowed by the state was the expensive military equipment.

Thorax1
An original bell-type thorax of the Greek Archaic period, with an extended bell-shaped protrusion of the waist for protection against enemy projectiles (arrows, stones and others).
.
The theory that the Lacedaemonians never used linen armor, is rather incorrect. The Spartan ‘omoioi‘ of the 6th-4th centuries BC rather used rarely linen cuirasses, which were suitable for the average Greek hoplite, but not for an elite force as they had been.  Every Spartan had an extensive farmstead which provided him the wherewithal to buy a bronze cuirass, so there was no reason to use a linen one (or a leather one). Additionally, his hard training gave him the necessary physical strength that was required for the use of metal armor, coupled with high military performance during the battle, which was very difficult to be achieved by the other Greek hoplites: it has been estimated that the hoplite military equipment including a brazen thorax, was weighing a total of approximately 30-35 kilos, i.e. a figure equal to about 50% of the weight of the average hoplite in accordance with the Mediterranean physique of this period.
However, it must be remembered that Lacedaemonians were not only the Spartans, but also the other free men of the state (but with no political rights) such as the ‘perioikoi’, ‘hypomeiones’ ‘xenoi trophimoi(περίοικοι, υπομείονες, ξένοι τρόφιμοι) and others, their total population numbering many times the population of the Spartans (in a ratio of about 6:1 at the time of the Peloponnesian War, according to a rather secure estimate). These ‘other Lacedaemonians’ (excluding the Spartans) holding not so wealthy farmsteads and generally having a low income overwhelmingly could not afford to buy metal armour. However, it is known that most of them fought as hoplites. This military role would require some kind of body armour, at least until shortly before the battle of Mantinea (418 BC), when the Spartan/Lacedaemonian army abandoned the use of armour. The Laconian archaeological findings of this era are supposed to depict specifically Spartans (omoioi), so they depict them bearing bronze armour. However, there are ancient references and archaeological evidence suggesting the use of body armour by the rest of the Lacedaemonians as well.

bell-muscle  cuirass

Cuirasses Marmesse

Above: Ancient Greek cuirasses of the intermediate phase between the bell-type cuirass and the muscled one. This type developed into the muscled cuirass of the Late Classical and the Hellenistic period.

Below: Celtic armour  from Gaul (Marmesse). The common elements with the Greek thoraxes of the upper photograph indicate the earliest interaction of the Late Mycenaean and the Proto-Celtic (Urnfield) cultures, possibly through trade or mercenary services. The foundation of the Greek colony Massalia (Marseilles) on the Mediterranean coast of Gaul strengthened these common elements.
.
Thucydides and Xenophon quote that the Lacedaemonians protected their torso with the ‘spolas‘ (σπολάς). Two dictionaries on the Antiquity, informs us that this term is generally equal to leather armour. This has probably been overestimated by several modern scholars, although these reports suggest that the exceptions were rather frequent. Sometimes the ‘spoladae‘ (in the plural) are mentioned by the ancient writers together with the ‘linothorakes‘ (linen cuirasses) confirming the reports of the dictionaries. In other cases, the term spolas seems to mean or include linen armour. Xenophon speaks of ‘spoladae‘ at a chronology (ca. 400 BC) during which the hoplites have abandoned any kind of body armour, as it is proved by many evidence, except thick fabric garment used as a thorax. For this reason, many scholars believe that Xenophon by the term ‘spolas‘ means the latter kind of body protection.

linos thorakas

Reconstruction of an ancient Greek linen cuirass (linothorax) by the University of Winsconsin-Green Bay (copyright holder).
.
In my opinion, the term ‘spolas‘ had a dual meaning: it meant the leather armour or generally any kind of armour that was not metal. I believe that the term ‘spolas‘ was born in a fairly early age, when leather was the primary material for body protection in the battle, and later included every cuirass that was not metal. It is also possible that the meaning of the term ‘spolas‘ differed depending on the geographical region and the people. The reference of Thucydides is confirmed by the Athenian reliefs of the 5th century BC, depicting Lacedaemonian arms and armour as spoils of war. These arms and armour are standard hoplite military equipment with the characteristic that the depicted thoraxes are obviously of the linen or leather types. However, their special depiction and their chronology (5th century BC) during which linen thorax had largely displaced the leather one across Greece, rather denote that their material was linen. These Athenian spoils of war came from various failures of Spartan expeditionary forces in operations outside the Peloponnesus. These forces were staffed by the other categories of Lacedaemonians with only a few Spartans (omoioi) among them, according to the policy of the Spartan regime not to send omoioi  in campaigns outside the Peloponnesus. The other Lacedaemonians were the majority of the men who staffed the lost Spartan garrison in Sphakteria (425 BC, a Spartan military disaster). I have already referred to the preference of the Spartans (‘omoioi‘) to the bronze cuirasses. Taking into consideration the aforementioned evidence and data, my conclusion is that the thoraxes (rather linothorakes) of the Athenian spoils of war belonged to the Lacedaemonian hoplites other than the Spartans.

aggeiografia
Ancient Greek  vase painting depicting a hoplite bearing linen armour. This is one of the sources for the reconstruction of the linen thorax of the photo.
.
The new tactics of hoplite warfare developed during the Peloponnesian War – particularly the need for greater flexibility during combat and for covering large distances during campaigns – , the financial problems of the warring sides and other factors, led the Spartans to the full abandonment of the torso armour before the battle of Mantinea (418 BC). This possibly took place at the first years of the Peloponnesian War and soon all the hoplite armies followed this trend. This trend remained until about the battle of Leuctra (371 BC). After this, body armor was reintroduced in the Spartan and the other Greek armies, especially the elegant muscled thorax  (first photo).
.
Periklis Deligiannis
.