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Where reliable foundation dates exist, articles should be categorised by year for 1500 and later, by decade from the 1300s to the 1490s, by century from the 10th century BC to the 13th century and by millennium for the 2nd millennium BC and earlier. Prior to 1500, where greater dating accuracy exists, articles should also be placed in the appropriate Establishments by year category. For any period in history, if reliable information does not narrow down the point of foundation beyond a given time period then articles should only be categorised by the most specific time period (i.e. decade, century or millennium) as indicated by reliable sources and without breaking the aforementioned scheme.