diff --git a/core/api/src/main/java/org/onlab/onos/mastership/MastershipEvent.java b/core/api/src/main/java/org/onlab/onos/mastership/MastershipEvent.java
new file mode 100644
index 0000000..bd7462d
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/mastership/MastershipEvent.java
@@ -0,0 +1,61 @@
+package org.onlab.onos.mastership;
+
+import org.onlab.onos.cluster.NodeId;
+import org.onlab.onos.event.AbstractEvent;
+import org.onlab.onos.net.DeviceId;
+
+/**
+ * Describes a device mastership event.
+ */
+public class MastershipEvent extends AbstractEvent<MastershipEvent.Type, DeviceId> {
+
+    //do we worry about explicitly setting slaves/equals? probably not,
+    //to keep it simple
+    NodeId master;
+
+    /**
+     * Type of mastership events.
+     */
+    public enum Type {
+        /**
+         * Signifies that the master for a device has changed.
+         */
+        MASTER_CHANGED
+    }
+
+    /**
+     * Creates an event of a given type and for the specified device, master,
+     * and the current time.
+     *
+     * @param type   device event type
+     * @param device event device subject
+     * @param master master ID subject
+     */
+    public MastershipEvent(Type type, DeviceId device, NodeId master) {
+        super(type, device);
+        this.master = master;
+    }
+
+    /**
+     * Creates an event of a given type and for the specified device, master,
+     * and time.
+     *
+     * @param type   mastership event type
+     * @param device event device subject
+     * @param master master ID subject
+     * @param time   occurrence time
+     */
+    public MastershipEvent(Type type, DeviceId device, NodeId master, long time) {
+        super(type, device, time);
+        this.master = master;
+    }
+
+    /**
+     * Returns the current master's ID as a subject.
+     *
+     * @return master ID subject
+     */
+    public NodeId master() {
+        return master;
+    }
+}