The oldest writing of Europe, unreadable for fifty years after its discovery, cracked by an architect on his kitchen table.
Documented
The decipherment is documented genius
Arthur Evans found the tablets at Knossos in 1900 and could not read them. Ventris, working with classicist John Chadwick, cracked the syllabary in 1952: the tablets were palace inventories in an early form of Greek, five centuries older than the alphabet. The decipherment pushed Europe's written history back half a millennium and destroyed the assumption that the script hid a lost language.
Assessment: Fully documented: the tablets, the decipherment papers, the scholarly acceptance. One of the few solved mysteries on this shelf, and the method, statistical analysis of sign patterns, is the same one failing on Linear A to this day.
Stories
The dark age carried Homer by mouth
Between Linear B's fall around 1200 BC and the alphabet's arrival around 800 BC, Greece had no writing at all, four centuries of silence. Yet the Iliad and Odyssey, set in the palace age, survived. Milman Parry proved how: the epics are built from oral formulas, memory technology, composed in performance across generations until someone finally wrote them down.
Assessment: Documented: the writing gap is archaeological fact, and Parry's oral-formulaic demonstration is one of the most solid results in classical scholarship. The greatest Greek texts were not written. They were remembered, mechanically, accurately, for four hundred years.
Interesting claims
The tablets were only the office files
The reading that keeps scholars honest: Linear B records are inventories, oil, wool, chariots, rations, with no literature at all. Palace Greek was written only for accountants. If the administration had not kept receipts, there would be no proof the palace age even spoke Greek. On this view, what survives of any civilization is its paperwork, and the poetry is always the first casualty.
Assessment: The contents of the tablets are documented: not one line of literature among thousands of records. The lesson it teaches about what survives is either profound or obvious, and the archive notes that every lost-text theory on this site rests on exactly this asymmetry.
Sources and further reading
Michael Ventris & John Chadwick, Evidence for Greek Dialect in the Mycenaean Archives, Journal of Hellenic Studies 73, 1953
The Pylos and Knossos tablet archives
Worth asking
Ventris proved Greek was written in 1400 BC. Homer was composed around 700 BC, in an age with no writing at all. So who wrote down the Iliad, and from whose memory?