The scheme applies primarily to pottery and is a relative dating system. The pottery at any given site typically can be ordered into early, middle and late on the basis of style and technique. The total time window allowed for the site is then divided into these periods proportionately. As it turns out, there is a correspondence between "early" over all Greece, etc. Also some "absolute dates" or dates obtained by non-comparative methods can be used to date the periods.
Absolute dates are preferable whenever they can be obtained. However, the relative structure was devised before the age of carbon dating. Most of the excavation was performed then as well. Typically only relative dates are obtainable. They form a structure for the characterization of Greek prehistory. Objects are generally dated by the pottery of the site found in associative contexts. Other objects can be arranged into early, middle and late as well, but pottery is used as a marker.
The three terms: Helladic, Cycladic, Minoan, refer to location of origin. Thus Middle Minoan objects might be found in the Cyclades. They are not on that account Middle Cycladic. The scheme tends to be less applicable on the periphery of the Aegean, such as the Levant. Pottery there might imitate Helladic or Minoan and yet be locally manufactured.
The "early", "middle" and "late" scheme can be applied at different levels. Rather than use such cumbersome terms as "early early" archaeologists by convention use I, II, III for the second level, A, B, C for the third level, 1, 2, 3 for the fourth level and a, b, c for the fifth. Not all levels are present at every site. If additional levels are required, another "early", "middle" or "late" can be appended. The Helladic period is subdivided as:
|Early Helladic I||2800-2500|
|Early Helladic II||2500-2300|
|Early Helladic III||2300-2100|
|Late Helladic I||1550-1500|
|Late Helladic II||1500-1400|
|Late Helladic III||1400-1060|
The Middle Helladic period corresponds in time to the Middle Kingdom of Egypt. Settlements draw more closely together and tend to be sited on hilltops. Middle Helladic sites are located throughout the Peloponnese and central Greece (including sites in the interior of Aetolia such as Thermon) as far north as the Spercheios River valley. Malthi in Messenia is the only Middle Helladic site to have been thoroughly excavated, but Lerna V will be the type site when it is fully published (Rutter).
Not found at Thera, but extant in late LHI from Messenia, and therefore likely commencing after the eruption, is a material culture known as "Peloponnesian LHI". This is characterised by "tall funnel-like Keftiu cups of Type III"; "small closed shapes such as squat jugs decorated with hatched loops ('rackets') or simplified spirals"; "dark-on-light lustrous-painted motifs", which "include small neat types of simple linked spiral such as varieties of hook-spiral or wave-spiral (with or without small dots in the field), forms of the hatched loop and double-axe, and accessorial rows of small dots and single or double wavy lines"; and also the "ripple pattern" on "Keftiu" cups. These local innovations continued into the LHIIA styles throughout the mainland.
The uniform and widely spread LHIIIA:1 pottery was originally defined by the material from the Ramp house at Mycenae, the palace at Thebes (now dated to LHIIIA:2 or LHIIIB by most researchers) and Triada at Rhodes. There is material from Asine, Athens (wells), Sparta (Menelaion), Nichoria and the 'Atreus Bothros', rubbish sealed under the Dromos of the Treasury of Atreus at Mycenae as well. C-14 dates from Tsoungiza indicate LHIIIA:1 should be more nearly 1435/1406 to 1390/1370 BC, slightly earlier than the pottery phase, but by less than 50 years. LHIIIA:1 ware has also been found in Maşat Höyük in Hittite Anatolia.
The LHIIIA:2 pottery marks a Mycenaean expansion covering most of the Eastern Mediterranean. There are many new shapes. The motifs of the painted pottery continue from LHIIIA:1 but show a great deal of standardization. In Egypt, the Amarna site contains LHIIIA:1 ware during the reign of Amenhotep III and LHIIIA:2 ware during that of his son Akhenaten; it also has the barest beginnings of LHIIIB. LHIIIA:2 ware is in the Uluburun shipwreck, which sank in the 14th century. Again, Tsoungiza dates are earlier, 1390/1370 to 1360/1325; but LHIIIA:2 ware also exists in a burn layer of Miletus which likely occurred early in Mursilis II's reign and therefore some years prior to Mursili's eclipse in 1312 BCE. The transition period between IIIA and IIIB begins after 1320 BCE, but not long after (Cemal Pulak thinks before 1295 BCE).
The definition of the LHIIIB by Furumark was mainly based on grave finds and the settlement material from Zygouries. It has been divided into two sub-phases by E. French, based on the finds from Mycenae and the West wall at Tiryns. LHIIIB:2 assemblages are sparse, as painted pottery is rare in tombs and many settlements of this period ended by destruction, leaving few complete pots behind.
LHIIIB pottery is associated in the Greek mainland palaces with the Linear B archives. (Linear B had been in use in Crete since Late Minoan II.) Pulak's proposed LHIIIA/B boundary would make LHIIIB contemporary in Anatolia with the resurgent Hittites following Mursili's eclipse; in Egypt with the 19th Dynasty, also known as the Ramessides; and in northern Mesopotamia with Assyria's ascendancy over Mitanni. The end of LHIIIB is associated with the destruction of Ugarit, whose ruins contain the last of that pottery. The Tsoungiza date for the end of LHIIIB is 1200/1190. The beginning of LHIIIC, therefore, is now commonly set into the reign of Queen Twosret. The LHIIIC has been divided into LHIIIC:1 and 2 by Furumark, based on materials from tombs in Mycenae, Asine, Kephalonia and Rhodes. In the 1960s, the excavations of the Citadel at Mycenae and of Lefkandi in Euboea yielded stratified material that allowed the ss. There is a lot of regional variation in the LHIIIC, especially in the later phases. Late LHIIIC pottery is found in Troy VIIa and a few pieces in Tarsus. It was also made locally in the Philistine settlements of Ashdod, Ashkelon, Ekron, Gath, and Gaza.