The Christian calendar was introduced in Rome only when the converted to Christianity. This system of dating is still used internationally. Using a

dating system makes it easier to mark and compare historical events.

In financial aspects, a depression is a sustained, long haul downturn in monetary movement in one or more economies. it is a more extreme monetary downturn than a recession, which is a slowdown in financial action through the span of a typical business cycle. a depression is an irregular and extreme type of recession. so depression is always followed by recession but it is not correct to state that a depression always follow a recession.