This visualization uses the XBRL instance document `xbrl-heraut.xml`, which records financial facts for the Dutch newspaper *De Heraut* from 1878 to 1887. The chart plots two time series extracted from the XBRL facts: annual subscription revenue (`abonnementen`) and advertising revenue (`advertentiën`), both in Dutch guilders (NLG), across yearly contexts (instant at December 31). The data, processed via an XQuery script (`xbrl-query.xqy`) that queries and orders the XBRL values, reveals revenue trends over the decade—subscriptions generally rising from roughly ƒ9,500 to a peak near ƒ14,500 in 1886, then dropping sharply to about ƒ8,400 in 1887, while advertising figures remain much smaller. The visualization likely pairs a line chart for subscriptions with a line or bar overlay for advertising revenue, highlighting the divergence in the final year and the dominance of subscription income for this historical Dutch newspaper. The concise example demonstrates how XBRL’s structured XML can be queried and transformed into a standard data frame for plotting.Here is a concise description for the visualization gallery, focusing on the data, its structure, and the story it tells. --- **Title:** Subscriptions vs. Advertisements: XBRL Financial Data for De Heraut (1878–1887) **Description:** This visualization uses a line chart to track the annual subscription and advertising revenue of the Belgian newspaper *De Heraut* from 1878 to 1887. The data is drawn from an XBRL instance document, a machine-readable format originally created for business reporting. This example repurposes that standard to encode historical financial facts for the newspaper over a decade. Each year forms a distinct context, with two financial facts recorded: subscription income and advertising income, both in Dutch guilders. The visualization reveals two starkly contrasting trends. Subscription revenue (in blue) dominates the overall scale and shows a pronounced spike in 1886, followed by a sharp collapse in 1887. Advertising revenue (in orange) remains comparatively low and stable over the same period, with only a slight rise from 1878 to 1887. Why this matters: The data, which comes from an XBRL instance document, shows how a standard business reporting format can be used to encode historical newspaper financials — enabling structured, queryable analysis of historical data. The visualization gallery entry can use a line chart to display the two trend lines over time, highlighting the volatile subscription line and the steadier advertising line. The clear separation of contexts and units in the XBRL file makes this a clean example of using XML-based business reporting for historical data. --- The above is the content for a data-visualization gallery. Add the title and a concise description. title: ... description: ... (2-4 sentences)## XBRL Instance Document for De Heraut This example visualizes subscription and advertising revenue data for the Dutch newspaper *De Heraut* (1878–1887), extracted from an XBRL instance document. The XBRL file marks up monetary facts using contexts for each fiscal year and the Netherlands Guilder (NLG) as the unit. A companion XQuery script parses the instance to pull out the subscription and profit/loss figures, enabling time-series comparison. This demonstrates how XBRL, an XML standard for business reporting, can be used to structure and query historical financial data.