Hemans, Frederick P. ‘Greek Architectural Terracotta from the Sanctuary of Poseidon at Isthmia’. Hesperia Supplements, Volume 27 (1994), pp. 61–83, 362–364, page 61.
Oscar Broneer: Isthmia, Vol. 1, Temple of Poseidon. Princeton (1971), Isthmia, Vol. 2, Topography and Architecture. Princeton (1973) and Isthmia, Vol. 3, Terracotta Lamps. Princeton (1977).
Rhodes, Robin F. ‘Early Corinthian Architecture and the Origins of the Doric Order.’ American Journal of Archaeology. Volume 91, Number 3 (July 1987), pp. 477–480, page 477.
Gebhard, Elizabeth R. and Hemans, Frederick P. University of Chicago Excavations at Isthmia, 1989: I. Hesperia, Volume 61, Number 1 (January 1992), pp. 1–77, pages 1–2
Grant, Michael. 1987. The Rise of the Greeks. London: Weidenfeld and Nicolson, page 88.
Roux, Georges. ‘Review: Isthmia, Vol. 1, Temple of Poseidon by Oscar Broneer.’ American Journal of Archaeology. Volume 78, Number 3 (July 1974), pp. 305–306, page 305
The first temple to Poseidon was built at Isthmia around 700 BC. The site at the Isthmus was a natural spot for the structure, since there were many ports nearby that served maritime traders. Around 480 BC, the archaic temple was destroyed by fire, and a new, larger temple in the Doric style was constructed in its place. In 390 BC, a Spartan Army marched on the Isthmus and damaged the temple again. The Doric building had a parastyle consisting of 7 x 19 wooden columns and measured ca. 38.10 by ca. 13.411 m at the stylobate; the Cella was ca. 7.70 by ca. 32.28 (?) m. The exterior walls were painted stone panels . After the archaic temple was destroyed by fire, a new temple, also Doric, was built to replace it. The new temple had 6 x 13 columns, and was erected before 450 B.C. Severely damaged by fire in 390 B.C., it was restored and remained standing until Early Christian times.
The temple floor plan was reconstructed as part of excavations conducted in 1989. There is little that remains of the structure other than the stylobate, however, the supporting pillars and dimensions indicate that it was of considerable size.
Archaic period temple of Poseidon at Isthmia