Ictinus (active second half of 5th century B.C.) was a Greek architect and the chief designer of the Parthenon. In addition, he is known to have prepared a design for the Telesterion, the great hall of the Mysteries at Eleusis.
Of what city Ictinus was a citizen is not known, but the importance of the building projects assigned to him in Athens makes it not unlikely that he was an Athenian. Like Phidias, he may have been part of a coterie of artists and intellectuals who were particularly favored by Pericles and who were assigned the task of formulating and giving external expression to the ideals of Periclean Athens.
The intellectual side of Ictinus's activity is confirmed by Vitruvius, who records the existence of a treatise about the Parthenon written by the architect and an associate named Carpion. This treatise presumably dealt with the well-known "refinements" of Greek temple architecture— proportional relationships, curvature of horizontal lines, and inclination of vertical members—which Ictinus brought to their highest point of development in the Parthenon.
Ictinus seems to have been particularly interested in the development of interior space in Greek architecture. In the Parthenon he integrated the colossal cult image of Athena with the cella in which it stood by using the superimposed rows of Doric columns which supported the ceiling of the cella as a three-sided frame for the image. He also incorporated elements of the Ionic order into the Doric cella— notably the famed Ionic frieze around its exterior and Ionic columns to support the ceiling of its west room. Both Vitruvius and the archeological evidence suggest that the distinctive feature of Ictinus's design for the Telesterion at Eleusis, a project never completed, was to reduce greatly the number of interior supports so that there would have been more unobstructed space than ever before for witnessing the most secret rites of the Mysteries.
The traveler Pausanias states that the temple at Bassae was a votive offering to Apollo for aid in averting the plague of 430/429 B.C. Some architectural historians find it difficult to believe that the old-fashioned exterior of this temple could have been built by Ictinus after his work on the Parthenon. The design of its interior, on the other hand, incorporating the first use of the Corinthian order, engaged Ionic columns, and an Ionic frieze, seems to represent an imaginative extension of the innovations in the Parthenon.
It may therefore be that the temple was begun by another architect around the middle of the fifth century B.C. but left unfinished for a time and that Ictinus was invited to complete it by designing its interior somewhat after 430 B.C.
The literary sources regarding Ictinus are collected in Jerome J. Pollitt, The Art of Greece, 1400-31 B.C.: Sources and Documents (1965). A detailed discussion of Ictinus's buildings is in William Bell Dinsmoor, The Architecture of Ancient Greece (1950). For illustrations see Helmut Berve and Gottfried Gruben, Greek Temples, Theatres, and Shrines (1963). The archeological evidence for the Telesterion at Eleusis is summarized in George E. Mylonas, Eleusis and the Eleusinian Mysteries (1961).