diff --git a/addon/model/model-range.ts b/addon/model/model-range.ts
index 5c2c53fb2..ca0e36252 100644
--- a/addon/model/model-range.ts
+++ b/addon/model/model-range.ts
@@ -323,7 +323,6 @@ export default class ModelRange {
       ),
     ] as ModelText[];
     if (nodes.length) {
-      console.log(nodes);
       let result = nodes[0].marks.clone();
       for (const node of nodes.slice(1)) {
         result = result.intersection(node.marks);
diff --git a/addon/model/util/datastore/datastore.ts b/addon/model/util/datastore/datastore.ts
index 8da2d8257..095ff1575 100644
--- a/addon/model/util/datastore/datastore.ts
+++ b/addon/model/util/datastore/datastore.ts
@@ -114,6 +114,16 @@ export default interface Datastore {
     action: (dataset: RDF.Dataset, termconverter: TermConverter) => RDF.Dataset
   ): Datastore;
 
+  /** Transformer method.
+   * Allows specifying of custom prefixes for use in the {@link match} method
+   * and the termConverter in the {@link transformDataset} method,
+   * or overwrite the ones that were scanned from the document.
+   *
+   * Reminder: only has an effect on the convenience "concise term syntax".
+   * Has no effect on the actual rdfa parsing.
+   */
+  withExtraPrefixes(prefixes: Record<string, string>): this;
+
   /**
    * Consumer method.
    * Returns a {@link TermMapping} of the currently valid subjects and the nodes that define them.
@@ -229,8 +239,12 @@ export class EditorStore implements Datastore {
       predicateToNodesMapping,
       nodeToPredicatesMapping,
       quadToNodesMapping,
+      seenPrefixes,
     } = RdfaParser.parse(config);
     const prefixMap = new Map<string, string>(Object.entries(defaultPrefixes));
+    for (const [key, value] of seenPrefixes.entries()) {
+      prefixMap.set(key, value);
+    }
 
     return new EditorStore({
       dataset,
@@ -301,6 +315,13 @@ export class EditorStore implements Datastore {
     });
   }
 
+  withExtraPrefixes(prefixes: Record<string, string>): this {
+    for (const [key, value] of Object.entries(prefixes)) {
+      this._prefixMapping.set(key, value);
+    }
+    return this;
+  }
+
   asSubjectNodeMapping(): TermMapping<RDF.Quad_Subject> {
     return new TermMapping<RDF.Quad_Subject>(
       this.subjectNodeGenerator(),
diff --git a/addon/utils/rdfa-parser/rdfa-parser.ts b/addon/utils/rdfa-parser/rdfa-parser.ts
index f19405825..3f7b4081f 100644
--- a/addon/utils/rdfa-parser/rdfa-parser.ts
+++ b/addon/utils/rdfa-parser/rdfa-parser.ts
@@ -70,6 +70,7 @@ export interface RdfaParseResponse {
   predicateToNodesMapping: Map<string, ModelNode[]>;
 
   quadToNodesMapping: Map<string, QuadNodes>;
+  seenPrefixes: Map<string, string>;
 }
 
 export class RdfaParser {
@@ -97,6 +98,7 @@ export class RdfaParser {
 
   private rootModelNode?: ModelNode;
   private seenNodes: Map<RDF.Term, ModelNode>;
+  private globallySeenPrefixes: Map<string, string>;
 
   constructor(options: IRdfaParserOptions) {
     this.options = options;
@@ -113,6 +115,7 @@ export class RdfaParser {
     this.rdfaPatterns = {};
     this.pendingRdfaPatternCopies = {};
     this.resultSet = new GraphyDataset();
+    this.globallySeenPrefixes = new Map<string, string>();
 
     this.nodeToSubjectMapping = new Map<ModelNode, ModelQuadSubject>();
     this.subjectToNodesMapping = new Map<string, ModelNode[]>();
@@ -186,6 +189,7 @@ export class RdfaParser {
       nodeToObjectsMapping: parser.nodeToObjectsMapping,
       objectToNodesMapping: parser.objectToNodesMapping,
       quadToNodesMapping: parser.quadToNodesMapping,
+      seenPrefixes: parser.globallySeenPrefixes,
     };
   }
 
@@ -386,7 +390,8 @@ export class RdfaParser {
     activeTag.prefixesCustom = Util.parsePrefixes(
       attributes,
       parentTag.prefixesCustom,
-      this.features.xmlnsPrefixMappings
+      this.features.xmlnsPrefixMappings,
+      this.globallySeenPrefixes
     );
     activeTag.prefixesAll =
       Object.keys(activeTag.prefixesCustom).length > 0
diff --git a/addon/utils/rdfa-parser/util.ts b/addon/utils/rdfa-parser/util.ts
index 1d584c6c7..bce6bc222 100644
--- a/addon/utils/rdfa-parser/util.ts
+++ b/addon/utils/rdfa-parser/util.ts
@@ -111,12 +111,14 @@ export class Util {
    * @param {{[p: string]: string}} attributes A tag's attributes.
    * @param {{[p: string]: string}} parentPrefixes The prefixes from the parent tag.
    * @param {boolean} xmlnsPrefixMappings If prefixes should be extracted from xmlnsPrefixMappings.
+   * @param globallySeenPrefixes Optionally keep track of all encountered prefixes
    * @return {{[p: string]: string}} The new prefixes.
    */
   public static parsePrefixes(
     attributes: { [s: string]: string },
     parentPrefixes: { [prefix: string]: string },
-    xmlnsPrefixMappings = false
+    xmlnsPrefixMappings = false,
+    globallySeenPrefixes?: Map<string, string>
   ): { [prefix: string]: string } {
     const additionalPrefixes: { [prefix: string]: string } = {};
     if (xmlnsPrefixMappings) {
@@ -137,6 +139,17 @@ export class Util {
         let prefixMatch = Util.PREFIX_REGEX.exec(attributes.prefix);
         while (prefixMatch) {
           prefixes[prefixMatch[1]] = prefixMatch[2];
+          if (globallySeenPrefixes) {
+            const key = prefixMatch[1];
+            const uri = prefixMatch[2];
+            const previousUri = globallySeenPrefixes.get(key);
+            if (previousUri && uri !== previousUri) {
+              console.warn(`Prefix ${key} is defined multiple times with a different uri.
+              Previous uri was ${previousUri}, now found ${uri}.
+              Will use latest value in concise-term-mapping logic`);
+            }
+            globallySeenPrefixes.set(key, uri);
+          }
           prefixMatch = Util.PREFIX_REGEX.exec(attributes.prefix);
         }
       }