You can filter results based on the date of creation of the archival material (which may differ from the time period you are interested in - e.g., philosophers from the Enlightenment period reflecting on classic thinkers). This filter will only include materials with "Full dates", i.e. those that include date information available for date-based searches. You can either search for a specific date of interest or focus step by step on the time span of a century, decade, year or month. When searching for a specific date, enter the date in the format DD-MM-YYYY, i.e. 01/01/1900 for 1 January 1900, via the calendar function or by typing directly in the text field.
This filter concentrates on the earliest dates mentioned in the materials.