In 1923 a Conference of Orthodox Churches in Constantinople refined the erroneous "Original" Julian Calendar. The technical correction was not much different than the 1582 version. As did Pope Gregory, so did the Orthodox Church refine the calendar by reducing the number of leap years, so that the average length of the civil calendar year would be nearer to the natural length of the solar year. By reducing the number of leap years in a 900-year cycle, the margin of difference was trimmed to 2.2 seconds a year which is virtually perfect. In this version, the Spring Equinox will arrive on March 21st for over 40,000 years.

Fascinating stuff.

Interesting read :)