Greece's official Athens News Agency says Constantine Stephanopoulos, a former president of Greece, has died.

Stephanopoulos, 90, had entered a hospital Thursday with pneumonia and his condition deteriorated rapidly. His doctors had released a statement Saturday saying he was suffering from multiple organ failure and was not responding to treatment.

Known widely by his first name diminutive Costis, Stephanopoulos was president from 1995 to 2005, serving the two full terms allowed by the Constitution.

Although the office is largely ceremonial, Stephanopoulos won wide popularity with his modesty and lack of bombast. Although a conservative, he got along very well with politicians across the spectrum, especially moderate socialist Costas Simitis, who was prime minister from 1996 to 2004.