Lord William Taylours excavations at Ayios Stephanos in 1959-77 investigated a port that relied on trade, fishing and metallurgy. It lay just north of the main Minoan east-west trade route via Kythera and exported the rare stone lapis lacedaemonius to Cretan workshops. As a Linear A inscription shows, the site illuminates the diffusion of Minoan culture to the mainland. Ayios Stephanos yielded a stratified pottery sequence from EH I to LH IIIC, with a break at the end of the Early Bronze Age. Study of this sequence has vastly improved our knowledge of the chronology, clarifying Cretan relations with the mainland. There were three phases of EH. After disastrous fires, rectangular buildings replaced the MH I apsidal dwellings, and the street plan came to resemble Minoan prototypes. The pottery illuminates the invention of Mycenaen ceramics. In line with the fortunes of Crete, the site declined in LH IIA, traded with Knossos in LH IIIA1, and declined again. It briefly revived in LH IIIC Early, probably following an influx of refugees. Then it was abandoned, perhaps after a massacre. Ayios Stephanos was reoccupied in c. 1270 AD, when a building with a walled yard and stables was erected to guard the approach to Skala along the River Vasilopotamos. This phase fills a gap in our knowledge, since no site of this period has been excavated south of Corinth. After 1321 a hostile raid plunged the site into oblivion. This publication studies the architecture and stratigraphy, the burials, the Medieval period, the pottery and small finds, the human and other organic remains, the settlement pattern and the regional and historical context. Numerous figures and plates document the results. Appendices containing techinical analyses, stratigraphic tables and concordances are on an accompanying CD.