Three Major Orders of Greek Architecture

To determine the facade of the temple, the ancient Greeks developed three major architectural orders, or styles: Doric , Ionic and Corinthian. The Doric is the oldest and simplest order. Ionic and Corinthian are more decorative and added more details to the structure. These orders also added a base to the column and developed details in the column’s capital. Each order shows different entablature (the part that rested above the columns), also.
The Doric order developed by the end of the 6th century BC, on the Greek mainland and southern Italy ad Sicily. It was the most simplest of the three orders. The columns are tapered and rest directly on the stylobate. There is no base to the columns. Doric column is between five and six times its diameter. The columns are made to bulge slightly. There is an inward curve to make the columns look straight, due to the optical illusion. This convex dilation is called entasis. Similarly, the stylobate billows slightly to make drainage easier and to counteract the illusion of a concave dip made by a flat base. In the Doric order, the use of almost universally approved proportions is significant. The earliest example is the Temple of Aphaia at Aegina, 490 BC. Parthenon is another example of the Doric order.
The Ionic order developed after the Doric order and adopted a lot from it. In the mature form of the Ionic order, the height was eight to nine times its diameter compared to the Doric. There were usually 24 flutes, even though the circumference was less. The column shaft usually had deeper flutes and is more slender than the Doric. Adjacent flutes were separated by a fillet and were rounded off at top and bottom. The typical ionic capital has two spiral volutes. Volutes are elements that look like partly unrolled scrolls. The Ionic capital looks different from the sides than from the front or the back. This difference caused problems in columns that stood at the corners. The volutes had to slant at the 45-degree angle so that their spiral pattern would look the same from the front of the temple as from the sides. The Ionic order is decorated with frieze and more carvings in the entablature. Ionic is more ornamental and graceful style than Doric but it lacks the clarity and power of the Doric style. The Temple of Artemis at Ephesus, the Temple of Athena Nike at the gateway of the Acropolis and the Temple of Artemis at Sardis in Asia Minor are some examples of the Ionic order.
The Corinthian order emerged late in the 5th century BC. It resembles the Ionic order in most aspects. The Corinthian capital makes a virtue of symmetry. The shape of the core is like an inverted bell. The volutes, borrowed from the Ionic order, are reduced to diagonally placed features at the corners. The rows of carved acanthus leaves are the main decorative effects achieved. The Corinthian column was at first used only for the interior columns and did not appeared externally until the 4th century BC. The Temple of Olympian Zeus at Athens in the 6th century is an example of the Corinthian order, when the Greeks began to build the Corinthian columns on the exterior.
In conclusion, there are three major orders in Greek architecture: Doric, Ionic and Corinthian. Each order adapted a lot from the previous orders. Doric order was the simplest and the oldest. Ionic and Corinthian developed base to the columns and gave a decorative appearance to the columns.