Context timelines

Context timelines let you read one timeline against others. You open a main timeline, add up to three more beneath it, and they all share one time axis: a family member's life with the century around it, a company's history with the industry's. Context is free on every plan, for anyone who can open a timeline, signed in or not. This article covers how to add it and take it away, how to share it, and what can't be lined up.

What a context timeline is

The main timeline is the one you opened. A context timeline is another timeline drawn as a muted strip below it, with its own header, its events above its line and its periods below. The strips use the main timeline's time axis, so when you drag or zoom, everything moves together. Strips stack in the order you added them, and a strip's chevron hides its body when you want the room back.

A strip writes its dates the way its own timeline does, so a timeline counted from an epoch still says age 26. A strip shows no uncertainty ranges, keeps its events to two label lanes and its periods to two lanes, and a period that doesn't fit is counted in the strip's header as +N periods not shown.

Add and remove context

The Add context button, with the layers icon, is in the toolbar at the bottom of the viewer; on a phone it is in the viewer menu. It opens a picker with a search field and these sections: Recently viewed, My timelines, Team timelines, Shared with me and Public timelines. Signed out, only Public timelines shows. Choose a row and its timeline appears as a strip. The main timeline is left out of the list, and a timeline that is already a strip is marked Added.

You can have three context timelines at a time. At three, the picker asks you to remove one before adding another and only offers the view setting. To remove one, use the close (X) button in its header. The title itself opens that timeline in a new tab.

When the ranges don't overlap

Each strip's header shows its timeline's range after the title, in that timeline's own dates. The view keeps to the main timeline's range, so a context timeline from another stretch of time can lie wholly outside it and its strip stays empty. The strip then says Outside this timeline's range, with a Widen the view to include it button: the view then reaches every strip's range and zooms out to show them all, and Home, End and the minimap cover the wider range too. A strip that is in reach but has nothing where you are looking says Nothing between, with the dates on screen, and Show its range zooms to its timeline.

To keep the view to the main timeline again, open Add context and clear Let the view span the context timelines too. The choice lives in the address along with the context, so a link you send opens with the same reach, and removing the last context timeline clears it.

Share the link

Context lives in the address of the page, not in the timeline. Nothing is saved: the timeline looks the same to everyone who opens it without your link. To show someone the same view, send them the address from your browser. They see the same strips, for the ones they are allowed to open. A strip they can't open shows This timeline isn't available, with a header they can remove.

A timeline opened through a share link can have context. Embeds, booklets, posters and captured images never include it. See sharing and visibility for how share links work.

What can't be lined up

Context needs real dates. A timeline with real dates, including one counted from an epoch that is anchored to a date, can be context and can take it, in any mix. A floating timeline, which counts from an epoch and has no real dates, can be neither. The picker lists one greyed out with No real dates, so it can't be lined up yet, and on a floating main timeline the Add context button explains instead of opening the picker. See dates, BCE and fuzzy dates for what floating means.

A timeline you can only open through a share link can't be added as context, because the link's secret would have to travel in the address for each strip.

Small screens

Strips need a horizontal timeline and enough height: the viewer needs room for the main timeline and a header for each strip. On a phone held upright, or in a window that is too short, no strips are drawn. The Add context button then explains why, and a link that carries context shows a notice you can dismiss. The context stays in the address, so turning the phone sideways or making the window larger brings the strips back.

Items in a strip

Choose an event or period in a strip and its details open in the side panel, read-only. Open in its timeline at the top takes you to that item on its own timeline. Editing and comments stay there: a context timeline you own is still edited from its own page. The search, the tag filter, the list and map views, the minimap and the assistant work on the main timeline only.