diff --git a/src/backend/concrete_history.cc b/src/backend/concrete_history.cc
index 90f52cd..fb2a379 100644
--- a/src/backend/concrete_history.cc
+++ b/src/backend/concrete_history.cc
@@ -290,6 +290,17 @@ ConcreteHistory::remove(SubRequest& subrequest)
 }
 
 
+void
+ConcreteHistory::clear()
+{
+  for_each(_snapshots.begin(), _snapshots.end(),
+           deletor<ConcreteEnvironment>());
+  _snapshots.clear();
+  _snapshots.push_back(new ConcreteEnvironment());
+  assert(_snapshots.size() == 1);
+}
+
+
 ConcreteHistory::ResourcePair
 ConcreteHistory::add_resource(const Glib::ustring& name,
                               bool   preemptable,
diff --git a/src/backend/concrete_history.hh b/src/backend/concrete_history.hh
index fbda2e2..479929d 100644
--- a/src/backend/concrete_history.hh
+++ b/src/backend/concrete_history.hh
@@ -60,6 +60,7 @@ namespace sgpem
     virtual void  remove(Request&    request);
     virtual void  remove(SubRequest& subrequest);
 
+    virtual void clear();
 
     virtual ResourcePair        add_resource(const Glib::ustring& name,
         bool   preemptable  = false,
diff --git a/src/backend/history.hh b/src/backend/history.hh
index 41e2665..a556cf6 100644
--- a/src/backend/history.hh
+++ b/src/backend/history.hh
@@ -77,6 +77,8 @@ namespace sgpem
     virtual void  remove(Request&    request)          = 0;
     virtual void  remove(SubRequest& subrequest)       = 0;
 
+    // \brief Clears the whole history
+    virtual void clear() = 0;
 
     virtual ResourcePair add_resource(const Glib::ustring& name,
                                       bool   preemptable  = false,