diff --git a/lib/header_pack.ml b/lib/header_pack.ml
index 07d0989..2d0b157 100644
--- a/lib/header_pack.ml
+++ b/lib/header_pack.ml
@@ -6,9 +6,21 @@ let of_set field t =
 	let add x a = Msgpck.String x :: a in
 	List.rev @@ String_set.fold add (Text.set field t) []
 
+let date = function
+	| None -> Int32.zero
+	| Some date ->
+		let days, ps = Ptime.Span.to_d_ps (Ptime.to_span date) in
+		Int32.add Int32.(mul (of_int days) 86400l) Int64.(to_int32 (div ps 1000000000000L))
+
+let columns = Msgpck.(List
+	[String "id"; String "time";  String "title";
+	 String "authors"; String "topics"; String "keywords"])
+
 let to_pack a t =
 	let open Text in
-	Msgpck.(List [Bytes (Id.to_bytes t.uuid); String t.title; List (persons t.authors);
+	Msgpck.(List [Bytes (Id.to_bytes t.uuid);
+		of_uint32 (date (Date.listing t.date));
+		String t.title; List (persons t.authors);
 		List (of_set "topics" t); List (of_set "keywords" t)]) :: a
 
 let pack_filename ?(filename="index.pck") archive =
@@ -28,32 +40,29 @@ let list filename = try
 	with Not_found -> Error "unspecified export dir"
 
 let contains text = function
-	| Msgpck.List (id::title::_authors::_topics::_keywords) ->
+	| Msgpck.List (id::_time::title::_authors::_topics::_keywords) ->
 		(match Id.of_bytes (Msgpck.to_bytes id) with
 		 | None -> prerr_endline ("Invalid id for " ^ Msgpck.to_string title); false
 		 | Some id -> text.Text.uuid = id)
 	| _ -> prerr_endline ("Invalid record pattern"); false
 
-let columns = Msgpck.(List [String "id"; String "title"; String "authors";
-	String "topics"; String "keywords"])
-
 let pack archive records =
-  let header_pack = List.fold_left to_pack [] records in
-  let archive = Msgpck.(List [Int 0; String archive.File_store.name;
-  	List (persons archive.archivists)]) in
-  Bytes.to_string @@ Msgpck.Bytes.to_string (List [archive; columns;
-  	Msgpck.List header_pack])
+	let header_pack = List.fold_left to_pack [] records in
+	let archive = Msgpck.(List [Int 0; String archive.File_store.name;
+		List (persons archive.archivists)]) in
+	Bytes.to_string @@ Msgpck.Bytes.to_string (List [archive; columns;
+		Msgpck.List header_pack])
 
 let add archive records =
 	let fname = pack_filename archive in
-  let append_fn published (t, _f) =
-    if List.exists (contains t) published then published
-    else to_pack published t in
-  match list fname with Error e -> prerr_endline e | Ok published_list ->
-    let header_pack = List.fold_left append_fn published_list records in
-    let archive = Msgpck.(List [Int 0; String archive.File_store.name;
-    	List (persons archive.archivists)]) in
-    File_store.file fname @@ Bytes.to_string @@ Msgpck.Bytes.to_string (List
-    	[archive; columns; Msgpck.List header_pack])
+	let append_fn published (t, _f) =
+		if List.exists (contains t) published then published
+		else to_pack published t in
+	match list fname with Error e -> prerr_endline e | Ok published_list ->
+		let header_pack = List.fold_left append_fn published_list records in
+		let archive = Msgpck.(List [Int 0; String archive.File_store.name;
+			List (persons archive.archivists)]) in
+		File_store.file fname @@ Bytes.to_string @@ Msgpck.Bytes.to_string (List
+			[archive; columns; Msgpck.List header_pack])
 
 let unpublish _archive _records = ()