diff --git a/xC-proto b/xC-proto
index 526cd0f..54ca6b8 100644
--- a/xC-proto
+++ b/xC-proto
@@ -71,7 +71,7 @@ struct EventMessage {
 			PART,
 			ACTION,
 		} rendition;
-		// Unix timestamp in seconds.
+		// Unix timestamp in milliseconds.
 		u64 when;
 		// Broken-up text, with in-band formatting.
 		union ItemData switch (enum Item {
diff --git a/xC.c b/xC.c
index 082b9fe..af2adbd 100644
--- a/xC.c
+++ b/xC.c
@@ -3105,7 +3105,7 @@ relay_prepare_buffer_line (struct app_context *ctx, struct buffer *buffer,
 	e->is_unimportant = !!(line->flags & BUFFER_LINE_UNIMPORTANT);
 	e->is_highlight = !!(line->flags & BUFFER_LINE_HIGHLIGHT);
 	e->rendition = 1 + line->r;
-	e->when = line->when;
+	e->when = line->when * 1000;
 
 	size_t len = 0;
 	for (size_t i = 0; line->items[i].type; i++)
diff --git a/xP/public/xP.js b/xP/public/xP.js
index c0dba93..f21683c 100644
--- a/xP/public/xP.js
+++ b/xP/public/xP.js
@@ -196,7 +196,7 @@ let Buffer = {
 
 		let lastDateMark = undefined
 		b.lines.forEach(line => {
-			let date = new Date(line.when * 1000)
+			let date = new Date(line.when)
 			let dateMark = date.toLocaleDateString()
 			if (dateMark !== lastDateMark) {
 				lines.push(m('.date', {}, dateMark))