Ianuarius (January)

Februarius (February)

Martius (March)

Aprilis (April)

Maius (May)

Iunius (June)

Iulius/Quintilis (July)

Augustus/Sextilis (August)

September (September)

October (October)

November (November)

December (December)

The original Roman calendar used the name Quintilis for July because in Latin Quintilis means fifth as in the fifth month. In the Roman calendar the year was structured to start in March (Martius), hence Quintilis was the fifth month. With the introduction of the Julian calendar (introduced by Julius Caesar), January (Ianuarius) became the first month and Julius Caesar named the month of July after himself. The old Roman calendar was based on the cycles of the moon, but the Julian calendar was based on the cycles of the sun. Some Orthodox churches still account for the days of the saints and holy feasts on the Julian calendar, but other than that the Julian calendar is no longer in use.