Each page spread in this Book of Centuries represents a period of time with space on the right to enter dates and information, and a blank page on the left where you can draw events or items of interest relating to the time period. Depending on the period a page represents from 1,000 years to 10 as follows- Prehistory - 3 spreads 6,000-3,000bc - 1,000 years per spread 2000bc-1600ad - 100 years per spread 1601-1800ad - 50 years per spread 1801-1900ad - 20 years per spread 1901-onwards - 10 years per spread