diff --git a/lib/architex.ex b/lib/architex.ex
index 8e282c7..414248f 100644
--- a/lib/architex.ex
+++ b/lib/architex.ex
@@ -271,4 +271,15 @@ defmodule Architex do
       end
     end
   end
+
+  # https://stackoverflow.com/a/45754361
+  def validate_not_nil(changeset, fields) do
+    Enum.reduce(fields, changeset, fn field, changeset ->
+      if Ecto.Changeset.get_field(changeset, field) == nil do
+        Ecto.Changeset.add_error(changeset, field, "nil")
+      else
+        changeset
+      end
+    end)
+  end
 end
diff --git a/lib/architex/schema/event.ex b/lib/architex/schema/event.ex
index a77c8a6..e924ae8 100644
--- a/lib/architex/schema/event.ex
+++ b/lib/architex/schema/event.ex
@@ -6,7 +6,7 @@ defmodule Architex.Event do
   alias Architex.{Repo, Room, Event, Account, EncodableMap, KeyServer}
   alias Architex.Types.UserId
 
-  # TODO: Could refactor to also always set prev_events, but not necessary.
+  # TODO: It seems unsigned is always set, even though it is not specified?
   @type t :: %__MODULE__{
           type: String.t(),
           origin_server_ts: integer(),
@@ -37,6 +37,7 @@ defmodule Architex.Event do
     belongs_to :room, Room, type: :string
   end
 
+  # TODO: Move this to a dedicated function in Event.Formatters.
   defimpl Jason.Encoder, for: Event do
     @pdu_keys [
       :auth_events,
diff --git a/lib/architex/schema/event/formatters.ex b/lib/architex/schema/event/formatters.ex
new file mode 100644
index 0000000..02407ca
--- /dev/null
+++ b/lib/architex/schema/event/formatters.ex
@@ -0,0 +1,26 @@
+defmodule Architex.Event.Formatters do
+  alias Architex.Event
+
+  def for_client(%Event{
+        content: content,
+        type: type,
+        id: event_id,
+        sender: sender,
+        origin_server_ts: origin_server_ts,
+        unsigned: unsigned,
+        room_id: room_id
+      }) do
+    data = %{
+      content: content,
+      type: type,
+      event_id: event_id,
+      sender: to_string(sender),
+      origin_server_ts: origin_server_ts,
+      room_id: room_id
+    }
+
+    data = if unsigned, do: Map.put(data, :unsigned, unsigned), else: data
+
+    data
+  end
+end
diff --git a/lib/architex/schema/room.ex b/lib/architex/schema/room.ex
index 5df8e4a..24fc07c 100644
--- a/lib/architex/schema/room.ex
+++ b/lib/architex/schema/room.ex
@@ -5,7 +5,7 @@ defmodule Architex.Room do
   import Ecto.Query
 
   alias Architex.{Repo, Room, Event, Alias, RoomServer}
-  alias ArchitexWeb.Client.Request.CreateRoom
+  alias ArchitexWeb.Client.Request.{CreateRoom, Messages}
 
   @type t :: %__MODULE__{
           visibility: :public | :private,
@@ -22,10 +22,12 @@ defmodule Architex.Room do
     has_many :aliases, Alias, foreign_key: :room_id
   end
 
+  @spec changeset(Room.t(), map()) :: Ecto.Changeset.t()
   def changeset(room, params \\ %{}) do
     cast(room, params, [:visibility])
   end
 
+  @spec create_changeset(CreateRoom.t()) :: Ecto.Changeset.t()
   def create_changeset(%CreateRoom{visibility: visibility}) do
     visibility = visibility || :public
 
@@ -33,10 +35,12 @@ defmodule Architex.Room do
     |> changeset(%{visibility: visibility})
   end
 
+  @spec generate_room_id() :: String.t()
   def generate_room_id do
     "!" <> Architex.random_string(18) <> ":" <> Architex.server_name()
   end
 
+  @spec update_forward_extremities(Event.t(), Room.t()) :: Room.t()
   def update_forward_extremities(
         %Event{
           id: event_id,
@@ -54,6 +58,7 @@ defmodule Architex.Room do
     room
   end
 
+  @spec create(Account.t(), CreateRoom.t()) :: {:ok, String.t()} | {:error, atom()}
   def create(account, input) do
     with {:ok, %Room{id: room_id}} <- Repo.insert(create_changeset(input)),
          {:ok, pid} <- RoomServer.get_room_server(room_id) do
@@ -62,4 +67,63 @@ defmodule Architex.Room do
       _ -> {:error, :unknown}
     end
   end
+
+  def get_messages(room, %Messages{from: from, to: to, dir: dir, limit: limit}) do
+    # TODO: Quaternion seems to show events in the wrong order?
+    # TODO: Check 'from' and 'to' formats.
+    limit = limit || 10
+
+    events =
+      room
+      |> Ecto.assoc(:events)
+      |> order_by_direction(dir)
+      |> events_from(from, dir)
+      |> events_to(to, dir)
+      |> limit(^limit)
+      |> Repo.all()
+
+    {events, get_start(events), get_end(events, limit)}
+  end
+
+  defp order_by_direction(query, "b"), do: order_by(query, desc: :origin_server_ts, desc: :nid)
+  defp order_by_direction(query, "f"), do: order_by(query, asc: :origin_server_ts, asc: :nid)
+
+  # When 'from' is empty, we return events from the start or end
+  # of the room's history.
+  defp events_from(query, "", _), do: query
+
+  defp events_from(query, from, "b") do
+    from = String.to_integer(from)
+    where(query, [e], e.nid < ^from)
+  end
+
+  defp events_from(query, from, "f") do
+    from = String.to_integer(from)
+    where(query, [e], e.nid > ^from)
+  end
+
+  defp events_to(query, nil, _), do: query
+
+  defp events_to(query, to, "b") do
+    to = String.to_integer(to)
+    where(query, [e], e.nid >= ^to)
+  end
+
+  defp events_to(query, to, "f") do
+    to = String.to_integer(to)
+    where(query, [e], e.nid <= ^to)
+  end
+
+  defp get_start([]), do: nil
+
+  defp get_start([%Event{nid: first_nid} | _]) do
+    Integer.to_string(first_nid)
+  end
+
+  defp get_end(events, limit) when length(events) < limit, do: nil
+
+  defp get_end(events, _) do
+    %Event{nid: last_nid} = List.last(events)
+    Integer.to_string(last_nid)
+  end
 end
diff --git a/lib/architex_web/client/controllers/login_controller.ex b/lib/architex_web/client/controllers/login_controller.ex
index 853bdc4..a9ab1b3 100644
--- a/lib/architex_web/client/controllers/login_controller.ex
+++ b/lib/architex_web/client/controllers/login_controller.ex
@@ -39,8 +39,7 @@ defmodule ArchitexWeb.Client.LoginController do
 
         case Account.login(input) |> Repo.transaction() do
           {:ok,
-           {%Account{localpart: localpart},
-            %Device{access_token: access_token, id: device_id}}} ->
+           {%Account{localpart: localpart}, %Device{access_token: access_token, id: device_id}}} ->
             data = %{
               user_id: Architex.get_mxid(localpart),
               access_token: access_token,
diff --git a/lib/architex_web/client/controllers/room_controller.ex b/lib/architex_web/client/controllers/room_controller.ex
index fdf895b..c330bdd 100644
--- a/lib/architex_web/client/controllers/room_controller.ex
+++ b/lib/architex_web/client/controllers/room_controller.ex
@@ -4,9 +4,9 @@ defmodule ArchitexWeb.Client.RoomController do
   import ArchitexWeb.Error
   import Ecto.{Changeset, Query}
 
-  alias Architex.{Repo, Room, RoomServer}
+  alias Architex.{Repo, Room, RoomServer, Event}
   alias Architex.Types.UserId
-  alias ArchitexWeb.Client.Request.{CreateRoom, Kick, Ban}
+  alias ArchitexWeb.Client.Request.{CreateRoom, Kick, Ban, Messages}
   alias Ecto.Changeset
   alias Plug.Conn
 
@@ -50,13 +50,9 @@ defmodule ArchitexWeb.Client.RoomController do
       |> select([jr], jr.id)
       |> Repo.all()
 
-    data = %{
-      joined_rooms: joined_room_ids
-    }
-
     conn
     |> put_status(200)
-    |> json(data)
+    |> json(%{joined_rooms: joined_room_ids})
   end
 
   @doc """
@@ -235,10 +231,32 @@ defmodule ArchitexWeb.Client.RoomController do
 
   # GET /_matrix/client/r0/rooms/!atYDsyowueiToUvuqY:localhost:4000/messages
   # Parameters: %{"dir" => "b", "from" => "", "limit" => "727", "path" => ["_matrix", "client", "r0", "rooms", "!atYDsyowueiToUvuqY:localhost:4000", "messages"]}
-  def message(conn, params) do
+  def messages(%Conn{assigns: %{account: account}} = conn, %{"room_id" => room_id} = params) do
+    # IO.inspect(Messages.changeset(%Messages{}, params))
 
-    conn
-    |> send_resp(400, [])
-    |> halt()
+    with {:ok, request} <- Messages.parse(params) do
+      room_query =
+        account
+        |> Ecto.assoc(:joined_rooms)
+        |> where([r], r.id == ^room_id)
+
+      case Repo.one(room_query) do
+        %Room{} = room ->
+          {events, start, end_} = Room.get_messages(room, request)
+          events = Enum.map(events, &Event.Formatters.for_client/1)
+          data = %{chunk: events}
+          data = if start, do: Map.put(data, :start, start), else: data
+          data = if end_, do: Map.put(data, :end, end_), else: data
+
+          conn
+          |> put_status(200)
+          |> json(data)
+
+        nil ->
+          put_error(conn, :forbidden, "You are not participating in this room.")
+      end
+    else
+      {:error, _} -> put_error(conn, :bad_json)
+    end
   end
 end
diff --git a/lib/architex_web/client/request/messages.ex b/lib/architex_web/client/request/messages.ex
new file mode 100644
index 0000000..e02c7e3
--- /dev/null
+++ b/lib/architex_web/client/request/messages.ex
@@ -0,0 +1,21 @@
+defmodule ArchitexWeb.Client.Request.Messages do
+  use ArchitexWeb.Request
+
+  @primary_key false
+  embedded_schema do
+    field :from, :string
+    field :to, :string
+    field :dir, :string
+    field :limit, :integer
+    field :filter, :string
+  end
+
+  def changeset(data, params) do
+    data
+    |> cast(params, [:from, :to, :dir, :limit, :filter], empty_values: [])
+    |> validate_required([:dir])
+    |> Architex.validate_not_nil([:from])
+    |> validate_inclusion(:dir, ["b", "f"])
+    |> validate_number(:limit, greater_than: 0)
+  end
+end
diff --git a/lib/architex_web/error.ex b/lib/architex_web/error.ex
index 12a4e9a..b8abc5e 100644
--- a/lib/architex_web/error.ex
+++ b/lib/architex_web/error.ex
@@ -6,7 +6,7 @@ defmodule ArchitexWeb.Error do
     bad_json: {400, "M_BAD_JSON", "Bad request."},
     user_in_use: {400, "M_USER_IN_USE", "Username is already taken."},
     invalid_username: {400, "M_INVALID_USERNAME", "Invalid username."},
-    forbidden: {400, "M_FORBIDDEN", "The requested action is forbidden."},
+    forbidden: {403, "M_FORBIDDEN", "The requested action is forbidden."},
     unrecognized: {400, "M_UNRECOGNIZED", "Unrecognized request."},
     unknown: {400, "M_UNKNOWN", "An unknown error occurred."},
     invalid_room_state:
diff --git a/priv/repo/migrations/20210830160818_create_initial_tables.exs b/priv/repo/migrations/20210830160818_create_initial_tables.exs
index f285edc..5f28c00 100644
--- a/priv/repo/migrations/20210830160818_create_initial_tables.exs
+++ b/priv/repo/migrations/20210830160818_create_initial_tables.exs
@@ -43,6 +43,7 @@ defmodule Architex.Repo.Migrations.CreateInitialTables do
     end
 
     create index(:events, [:id], unique: true)
+    create index(:events, [:origin_server_ts])
 
     create table(:server_key_info, primary_key: false) do
       add :valid_until, :bigint, default: 0, null: false
@@ -80,7 +81,10 @@ defmodule Architex.Repo.Migrations.CreateInitialTables do
 
     create table(:device_transactions, primary_key: false) do
       add :txn_id, :string, primary_key: true, null: false
-      add :device_nid, references(:devices, column: :nid, on_delete: :delete_all), primary_key: true
+
+      add :device_nid, references(:devices, column: :nid, on_delete: :delete_all),
+        primary_key: true
+
       add :event_id, :string, null: false
     end
   end