Linear B Script was the writing system used by the Mycenaean civilization. Examples of this script have been recovered from late Minoan II contexts in Crete and Mycenaean IIIA-B contexts in mainland Greece, which suggest that the script was in use broadly between 1450 and 1100 BCE. The use of Linear B Script was restricted to major palace sites such as Knossos, Mycenae, Pylos, Thebes, and Tiryns. Most Linear B inscriptions are on clay tablets and largely concerned with documenting economic transactions of the palace administration, but we also have a few examples that relate to military activity.
The Greeks were not the only ones who employed a syllabic writing system: several syllabic scripts were used by different contemporary Near-Eastern neighbours. The Linear B writing system is composed of 90 syllable signs plus an indeterminate number of pictorial signs. Each syllable sign represents either a vowel or an open syllable (consonant-vowel), but they cannot represent consonant clusters.
ORIGIN OF THE LINEAR B SCRIPT
Linear B is the oldest preserved form of written Greek that we know of. By the time we first meet this writing system, Greece and different areas of the western coast of Asia Minor were already Greek-speaking. Linear B was used to write an archaic form of Greek known as Mycenaean Greek, which was the official dialect of the Mycenaean civilization. The inscriptions found in Crete appear to be older than those discovered in mainland Greece. The oldest confirmed Linear B tablets are the so-called Room of the Chariot Tablets from Knossos and have been dated to c.1450-1350 BCE, while the tablets found at Pylos have been dated to c. 1200 BCE. This suggests that the Linear B script was devised in Knossos (Crete), somewhere around 1450 BCE when the Mycenaeans took control of Knossos, and spread from here to mainland Greece. Whether by peaceful annexation or armed invasion, we know that the Minoan culture was replaced, both in Crete and in mainland Greece, by the Mycenaean culture.
Long before the Mycenaeans took control of Knossos, the Minoan civilization had a writing system in use known as Linear A Script, which was employed to represent the official Minoan language. Nothing certain is known about the Minoan language. Its linguistic affiliation remains a mystery, but the general consensus is that the language was not Greek; probably it was not even part of the Indo-European languages. […]
(From Ancient History Encyclopaedia, Cristian Violatti, 26.01.2015)