diff --git a/README.md b/README.md
index 7299e3d..fc59211 100644
--- a/README.md
+++ b/README.md
@@ -30,10 +30,11 @@ defmodule CreateAccount do
   use Commanded.Command,
       username: :string,
       email: :string,
-      age: :integer
+      age: {:integer, default: 0},
+      aliases: {{:array, :string}} # Composite Type requires extra brace to avoid being interprated as opts
 end
 
-iex> CreateAccount.new() 
+iex> CreateAccount.new()
 #Ecto.Changeset<action: nil, changes: %{}, errors: [], data: #CreateAccount<>, valid?: true>
 ```
 
@@ -54,7 +55,7 @@ defmodule CreateAccount do
   end
 end
 
-iex> CreateAccount.new() 
+iex> CreateAccount.new()
 #Ecto.Changeset<
   action: nil,
   changes: %{},
@@ -67,7 +68,7 @@ iex> CreateAccount.new()
   valid?: false
 >
 
-iex> changeset = CreateAccount.new(username: "chris", email: "chris@example.com", age: 5) 
+iex> changeset = CreateAccount.new(username: "chris", email: "chris@example.com", age: 5)
 #Ecto.Changeset<
   action: nil,
   changes: %{age: 5, email: "chris@example.com", username: "chris"},
@@ -149,7 +150,7 @@ iex> event = AccountCreated.new(cmd)
 
 You may have noticed that we provide a default version of `1`.
 
-You can change the version of an event at anytime. 
+You can change the version of an event at anytime.
 
 After doing so, you should define an upcast instance that knows how to transform older events into the latest version.
 
diff --git a/lib/commanded/command.ex b/lib/commanded/command.ex
index 7cc197d..7652ae3 100644
--- a/lib/commanded/command.ex
+++ b/lib/commanded/command.ex
@@ -6,18 +6,19 @@ defmodule Commanded.Command do
         use Commanded.Command,
           username: :string,
           email: :string,
-          age: :integer
+          age: :integer,
+          aliases: {{:array, :string}}
 
         def handle_validate(changeset) do
           changeset
-          |> validate_required([:username, :email, :age])
+          |> validate_required([:username, :email, :age, :aliases])
           |> validate_format(:email, ~r/@/)
           |> validate_number(:age, greater_than: 12)
         end
       end
 
-      iex> CreateAccount.new(username: "chris", email: "chris@example.com", age: 5)
-      #Ecto.Changeset<action: nil, changes: %{age: 5, email: "chris@example.com", username: "chris"}, errors: [age: {"must be greater than %{number}", [validation: :number, kind: :greater_than, number: 12]}], data: #CreateAccount<>, valid?: false>
+      iex> CreateAccount.new(username: "chris", email: "chris@example.com", age: 5, aliases: ["christopher", "kris"])
+      #Ecto.Changeset<action: nil, changes: %{age: 5, aliases: ["christopher", "kris"], email: "chris@example.com", username: "chris"}, errors: [age: {"must be greater than %{number}", [validation: :number, kind: :greater_than, number: 12]}], data: #CreateAccount<>, valid?: false>
   """
 
   @doc """
@@ -35,6 +36,8 @@ defmodule Commanded.Command do
       @primary_key false
       embedded_schema do
         Enum.map(unquote(schema), fn
+          {name, {{_, _} = composite_type, opts}} -> field(name, field_type(composite_type), opts)
+          {name, {{_, _} = composite_type}} -> field(name, field_type(composite_type))
           {name, {type, opts}} -> field(name, field_type(type), opts)
           {name, type} -> field(name, field_type(type))
         end)
@@ -60,5 +63,8 @@ defmodule Commanded.Command do
   end
 
   def field_type(:binary_id), do: Ecto.UUID
+  def field_type(:array) do
+    raise "`:array` is not a valid Ecto.Type\nIf you are using a composite data type, wrap the type definition like this `{{:array, :string}}`"
+  end
   def field_type(type), do: type
 end
diff --git a/test/support/messages.ex b/test/support/messages.ex
index f403792..236c792 100644
--- a/test/support/messages.ex
+++ b/test/support/messages.ex
@@ -9,7 +9,8 @@ defmodule CreateAccount do
   use Commanded.Command,
     username: :string,
     email: :string,
-    age: :integer
+    age: :integer,
+    aliases: {{:array, :string}}
 
   def handle_validate(changeset) do
     changeset