diff --git a/main.js b/main.js
index 8af3c46..cbf9974 100644
--- a/main.js
+++ b/main.js
@@ -32,6 +32,9 @@ logger.level = settings.loglevel;
 logger.info("Log initialized.");
 var initialsynccomplete = false;
 
+// Save script start time for ignoring older messages
+var boottimestamp = Date.now();
+
 // https://github.com/matrix-org/matrix-js-sdk/issues/2415#issuecomment-1188812401
 matrixcs.request(request);
 
@@ -499,13 +502,18 @@ client.on("Room.timeline", function (event, room) {
         }
         if (event.getTs() < (Date.now() - 1000 * 60 * 60 * 8)) {
             // Ignore old events (8 hrs), they're probably duplicates or something.
-            logger.info("Ignoring stale Matrix room event");
+            logger.warning("Ignoring stale Matrix room event [" + event.getId() + "]: older than 8 hours");
+            return;
+        }
+        if (event.getTs() < boottimestamp) {
+            logger.warning("Ignoring stale Matrix room event [" + event.getId() + "]: event predates start of this program");
             return;
         }
         if (event.getContent() == null || typeof event.getContent().body == "undefined" || event.getContent().body == null) {
             // Apparently this can happen?
             return;
         }
+        logger.debug("Got room message (event ID " + event.getId() + ")");
 
         if (event.getContent().body.toLowerCase().startsWith("!sms")) {
             // capture command to start room for new number