I would like to discuss the visualisation of time lines. Since this is a form of one-dimensional mapping, I thought this might be the right place to discuss this.
I've been toying with some form of graphical presentation of the position of an event relative to a timeline. Known dates are easy, they form a sharp coordinate, often sharper than the graphical representation allows to convey unless you zoom in. Vague dates like "during the reign of X" let you use the (hopefully known) beginning and ending of that reign as the time bracket, and display the event as a probability bar less than solid.
An even more vague date like "when Saronil was old, or in the first years of the reign of his successor Jarolar" could be represented as a less than solid colored bar (line object) with heightened intensity for the most likely time frame (around Saronil's death), and fading off resembling a Gaussian bell curve distribution towards the less likely extremes of the time span.
Ideally such data would be generated from a database which can apply thematic, geographic and topological filtering, displaying such data with indicators for relevance which may be adjusted for each such display. You don't have to go towards a GIS, just giving an event associations with locations/regions, people or organisations participating and the flavor of the event could allow to calculate a metric for relevance (hence "topological filtering" through known relations).
When asking "what happened in/about <date>", a list of matches would be generated, probably prefaced with a selection of broader data about the broader temporal bracket (e.g. millennium, century, decade, year). I used a relational database with unspecified entries which then were assigned categories (from a limited list of choices like person, office, city, country) and related entries (a single unidirectonal table labeled "see also", which may be reciprocal, and which may get a descriptor about the nature of the relation).
If King X founded city Y at a date in relation to event or time frame Z, this would create a number of "see also" entries. Both the person King X and the city (a category in itself) Y would have other relationships, like e.g. a country (not necessarily the same for both), other locations (roads, rivers, valleys, forests for the city, places visited for the person). If the city is situated on a river or a trade route, it would create a timeline entry for queries about the river or the trade route.
I think it should be possible to use/abuse mapping software to create such displays.