diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..c358ee4
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,23 @@
+# Changelog
+
+All notable changes to this project will be documented in this file.
+
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
+
+## [Unreleased]
+
+## [1.0.0-alpha2] - 2023-07-31
+
+### Added
+
+- Add a method to set a prefix.
+- Add this changelog file.
+
+## [1.0.0-alpha1] - 2023-07-28
+
+- Initial release.
+
+[unreleased]: https://github.com/assemblee-virtuelle/semantizer-php/compare/v1.0.0-alpha2...HEAD
+[1.0.0-alpha2]: https://github.com/assemblee-virtuelle/semantizer-php/compare/v1.0.0-alpha1...v1.0.0-alpha2
+[1.0.0-alpha1]: https://github.com/assemblee-virtuelle/semantizer-php/releases/tag/v1.0.0-alpha1
diff --git a/composer.json b/composer.json
index d58067d..4f19bc4 100644
--- a/composer.json
+++ b/composer.json
@@ -1,7 +1,7 @@
 {
     "name": "virtual-assembly/semantizer",
     "type": "library",
-    "version": "1.0.0-alpha1",
+    "version": "1.0.0-alpha2",
     "description": "A library to enhance your object model with semantic data.",
     "keywords": ["semantic web","rdf","object model"],
     "homepage": "https://github.com/assemblee-virtuelle/semantizer-php",
diff --git a/src/Semantizer.php b/src/Semantizer.php
index 5b6869d..8aa19b3 100644
--- a/src/Semantizer.php
+++ b/src/Semantizer.php
@@ -41,6 +41,10 @@ public function fetch(string $semanticObjectId): Semanticable {
         return $this->store->get($semanticObjectId);
     }
 
+    public function setPrefix(string $prefix, string $uri): void {
+        \EasyRdf\RdfNamespace::set($prefix, $uri);
+    }
+
     public function store(Semanticable $semanticable): void {
         $this->store->set($semanticable);
     }
diff --git a/tests/SemantizerTest.php b/tests/SemantizerTest.php
index 978fe73..9a07d79 100644
--- a/tests/SemantizerTest.php
+++ b/tests/SemantizerTest.php
@@ -7,7 +7,7 @@ final class SemantizerTest extends TestCase
 {
     public function testExport(): void {
         $semantizer = new Semantizer();
-        \EasyRdf\RdfNamespace::set("dfc", "https://github.com/datafoodconsortium/ontology/releases/latest/download/DFC_BusinessOntology.owl#");
+        $semantizer->setPrefix("dfc", "https://github.com/datafoodconsortium/ontology/releases/latest/download/DFC_BusinessOntology.owl#");
 
         $context = ["https://www.datafoodconsortium.org"];