diff --git a/examples/meta/main.go b/examples/meta/main.go
index 4781da4..0512742 100644
--- a/examples/meta/main.go
+++ b/examples/meta/main.go
@@ -7,6 +7,7 @@ import (
 	"time"
 
 	"github.com/recentralized/structure/data"
+	"github.com/recentralized/structure/index"
 	"github.com/recentralized/structure/meta"
 )
 
@@ -28,6 +29,8 @@ func main() {
 
 func buildMeta() (*meta.Meta, error) {
 
+	srcID := index.SrcID("e8400c72-f7d0-53f9-98ca-ee23238231fe")
+
 	doc := meta.New()
 	doc.Type = data.JPG
 	doc.Size = 1024
@@ -42,9 +45,13 @@ func buildMeta() (*meta.Meta, error) {
 			"ExposureTime": meta.ExifValue{ID: "ShutterSpeed", Val: "1/60"},
 		},
 	}
-	doc.Sidecar = meta.Content{
-		Exif: meta.Exif{
-			"FNumber": meta.ExifValue{ID: "0x829d", Val: 1.8},
+	doc.Src = map[index.SrcID]meta.SrcSpecific{
+		srcID: {
+			Sidecar: &meta.Content{
+				Exif: meta.Exif{
+					"FNumber": meta.ExifValue{ID: "0x829d", Val: 1.8},
+				},
+			},
 		},
 	}
 
diff --git a/examples/meta/output.json b/examples/meta/output.json
index 04ff190..425ff87 100644
--- a/examples/meta/output.json
+++ b/examples/meta/output.json
@@ -15,11 +15,15 @@
       }
     }
   },
-  "sidecar": {
-    "exif": {
-      "FNumber": {
-        "id": "0x829d",
-        "val": 1.8
+  "src": {
+    "e8400c72-f7d0-53f9-98ca-ee23238231fe": {
+      "sidecar": {
+        "exif": {
+          "FNumber": {
+            "id": "0x829d",
+            "val": 1.8
+          }
+        }
       }
     }
   }
diff --git a/meta/encoding.go b/meta/encoding.go
index 86bb4cb..98c8b7b 100644
--- a/meta/encoding.go
+++ b/meta/encoding.go
@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"github.com/recentralized/structure/data"
+	"github.com/recentralized/structure/index"
 )
 
 type metaJSON struct {
@@ -12,24 +13,34 @@ type metaJSON struct {
 	Type        data.Type `json:"type"`
 	ContentType data.Type `json:"content_type,omitempty"`
 	Size        int64     `json:"size"`
-	Inherent    *Content  `json:"inherent,omitempty"`
-	Sidecar     *Content  `json:"sidecar,omitempty"`
-	SrcSpecific           // Embedded fields.
+
+	Inherent *Content                    `json:"inherent,omitempty"`
+	Src      map[index.SrcID]SrcSpecific `json:"src,omitempty"`
+
+	// V0 Fields
+	Sidecar       *Content `json:"sidecar,omitempty"`
+	V0SrcSpecific          // Embedded fields.
 }
 
 // MarshalJSON converts Meta to JSON.
 func (m Meta) MarshalJSON() ([]byte, error) {
 	j := metaJSON{
-		Version:     m.Version,
-		Type:        m.Type,
-		Size:        m.Size,
-		SrcSpecific: m.Srcs,
+		Version:       m.Version,
+		Type:          m.Type,
+		Size:          m.Size,
+		V0SrcSpecific: m.V0Srcs,
 	}
 	if !m.Inherent.isZero() {
 		j.Inherent = &m.Inherent
 	}
-	if !m.Sidecar.isZero() {
-		j.Sidecar = &m.Sidecar
+	if !m.V0Sidecar.isZero() {
+		j.Sidecar = &m.V0Sidecar
+	}
+	if m.Src != nil {
+		j.Src = make(map[index.SrcID]SrcSpecific)
+		for k, v := range m.Src {
+			j.Src[k] = v
+		}
 	}
 	return json.Marshal(j)
 }
@@ -46,13 +57,19 @@ func (m *Meta) UnmarshalJSON(data []byte) error {
 		m.Type = j.ContentType
 	}
 	m.Size = j.Size
+	if j.Src != nil {
+		m.Src = make(map[index.SrcID]SrcSpecific)
+		for k, v := range j.Src {
+			m.Src[k] = v
+		}
+	}
 	if j.Inherent != nil {
 		m.Inherent = *j.Inherent
 	}
 	if j.Sidecar != nil {
-		m.Sidecar = *j.Sidecar
+		m.V0Sidecar = *j.Sidecar
 	}
-	m.Srcs = j.SrcSpecific
+	m.V0Srcs = j.V0SrcSpecific
 	return nil
 }
 
diff --git a/meta/encoding_test.go b/meta/encoding_test.go
index f53e663..2eaaf76 100644
--- a/meta/encoding_test.go
+++ b/meta/encoding_test.go
@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/recentralized/structure/data"
+	"github.com/recentralized/structure/index"
 )
 
 func TestMetaJSON(t *testing.T) {
@@ -28,6 +29,13 @@ func TestMetaJSON(t *testing.T) {
 				Version: "v1",
 				Type:    data.JPG,
 				Size:    100,
+			},
+			json: `{"version":"v1","type":"jpg","size":100}`,
+		},
+		{
+			desc: "inherent",
+			meta: Meta{
+				Version: "v1",
 				Inherent: Content{
 					Created: time.Date(1, 2, 3, 4, 5, 6, 7, time.UTC),
 					Image: Image{
@@ -41,23 +49,66 @@ func TestMetaJSON(t *testing.T) {
 						},
 					},
 				},
-				Sidecar: Content{
-					Created: time.Date(2, 2, 3, 4, 5, 6, 7, time.UTC),
+			},
+			json: `{"version":"v1","type":"","size":0,"inherent":{"created":"0001-02-03T04:05:06.000000007Z","image":{"width":100,"height":60},"exif":{"CreateData":{"id":"0x9004","val":"2013:07:17 19:59:58"}}}}`,
+		},
+		{
+			desc: "src-specific: sidecar",
+			meta: Meta{
+				Version: "v1",
+				Src: map[index.SrcID]SrcSpecific{
+					index.SrcID("s1"): {
+						Sidecar: &Content{
+							Created: time.Date(1, 2, 3, 4, 5, 6, 7, time.UTC),
+							Image: Image{
+								Width:  100,
+								Height: 60,
+							},
+							Exif: Exif{
+								"CreateData": ExifValue{
+									ID:  "0x9004",
+									Val: "2013:07:17 19:59:58",
+								},
+							},
+						},
+					},
 				},
 			},
-			json: `{"version":"v1","type":"jpg","size":100,"inherent":{"created":"0001-02-03T04:05:06.000000007Z","image":{"width":100,"height":60},"exif":{"CreateData":{"id":"0x9004","val":"2013:07:17 19:59:58"}}},"sidecar":{"created":"0002-02-03T04:05:06.000000007Z"}}`,
+			json: `{"version":"v1","type":"","size":0,"src":{"s1":{"sidecar":{"created":"0001-02-03T04:05:06.000000007Z","image":{"width":100,"height":60},"exif":{"CreateData":{"id":"0x9004","val":"2013:07:17 19:59:58"}}}}}}`,
 		},
 		{
-			desc: "src-specific fields: flickr",
+			desc: "src-specific: flickr",
 			meta: Meta{
 				Version: "v1",
-				Srcs: SrcSpecific{
-					Flickr: &FlickrMedia{
-						ID: "123",
+				Src: map[index.SrcID]SrcSpecific{
+					index.SrcID("s1"): {
+						Flickr: &FlickrMedia{
+							ID: "123",
+						},
 					},
 				},
 			},
-			json: `{"version":"v1","type":"","size":0,"flickr":{"id":"123"}}`,
+			json: `{"version":"v1","type":"","size":0,"src":{"s1":{"flickr":{"id":"123"}}}}`,
+		},
+		{
+			desc: "v0 sidecar",
+			meta: Meta{
+				Version: "v1",
+				V0Sidecar: Content{
+					Created: time.Date(2, 2, 3, 4, 5, 6, 7, time.UTC),
+				},
+			},
+			json: `{"version":"v1","type":"","size":0,"sidecar":{"created":"0002-02-03T04:05:06.000000007Z"}}`,
+		},
+		{
+			desc: "v0 src-specific",
+			meta: Meta{
+				Version: "v1",
+				V0Srcs:  V0SrcSpecific{
+					//Flickr:
+				},
+			},
+			json: `{"version":"v1","type":"","size":0}`,
 		},
 	}
 	for _, tt := range tests {
diff --git a/meta/meta.go b/meta/meta.go
index 0ee976d..b5f74b9 100644
--- a/meta/meta.go
+++ b/meta/meta.go
@@ -4,9 +4,11 @@ import (
 	"encoding/json"
 	"errors"
 	"io"
+	"sort"
 	"time"
 
 	"github.com/recentralized/structure/data"
+	"github.com/recentralized/structure/index"
 )
 
 const (
@@ -34,12 +36,17 @@ type Meta struct {
 	// Metadata that came from the content itself.
 	Inherent Content
 
+	// Metadata that came from elsewhere on the source.
+	Src map[index.SrcID]SrcSpecific
+
 	// Metadata that came from nearby, such as an XMP sidecar file or other
 	// source of metadata.
-	Sidecar Content
+	// Deprecated: Read from V0 only. Use Src[srcID] instead.
+	V0Sidecar Content
 
 	// Metadata that came from the source of the data.
-	Srcs SrcSpecific
+	// Deprecated: Read from V0 only. Use Src[srcID] instead.
+	V0Srcs V0SrcSpecific
 }
 
 // New initializes a new Meta at the current version.
@@ -70,9 +77,17 @@ func ParseJSON(r io.Reader) (*Meta, error) {
 // time available it returns time.Time's zero value.
 func (m *Meta) DateCreated() time.Time {
 	times := []time.Time{
-		m.Sidecar.Created,
+		m.V0Sidecar.Created,
 		m.Inherent.Created,
 	}
+	if len(m.Src) > 0 {
+		for _, v := range m.Src {
+			if v.Sidecar != nil {
+				times = append(times, v.Sidecar.Created)
+			}
+		}
+		sort.Slice(times, func(i, j int) bool { return times[i].Before(times[j]) })
+	}
 	for _, t := range times {
 		if !t.IsZero() {
 			return t
@@ -102,7 +117,13 @@ type Image struct {
 
 // SrcSpecific contains source-specific metadata.
 type SrcSpecific struct {
-	Flickr *FlickrMedia `json:"flickr,omitempty"`
+	Sidecar *Content     `json:"sidecar,omitempty"`
+	Flickr  *FlickrMedia `json:"flickr,omitempty"`
+}
+
+// V0SrcSpecific contains source-specific metadata.
+type V0SrcSpecific struct {
+	// TODO: port v0 sources
 }
 
 func (m Content) isZero() bool {
diff --git a/meta/meta_test.go b/meta/meta_test.go
index c4ffd84..9876949 100644
--- a/meta/meta_test.go
+++ b/meta/meta_test.go
@@ -4,6 +4,8 @@ import (
 	"reflect"
 	"testing"
 	"time"
+
+	"github.com/recentralized/structure/index"
 )
 
 func TestMetaDateCreated(t *testing.T) {
@@ -24,25 +26,43 @@ func TestMetaDateCreated(t *testing.T) {
 			want: time.Date(2001, 1, 1, 1, 1, 1, 1, time.UTC),
 		},
 		{
-			desc: "sidecar with date",
+			desc: "oldest of inherent or sidecars",
 			m: &Meta{
-				Sidecar: Content{Created: time.Date(2001, 2, 1, 1, 1, 1, 1, time.UTC)},
+				Inherent: Content{Created: time.Date(2009, 1, 1, 1, 1, 1, 1, time.UTC)},
+				Src: map[index.SrcID]SrcSpecific{
+					index.SrcID("a"): {
+						Sidecar: &Content{Created: time.Date(2004, 1, 1, 1, 1, 1, 1, time.UTC)},
+					},
+					index.SrcID("b"): {
+						Sidecar: &Content{Created: time.Date(2001, 1, 1, 1, 1, 1, 1, time.UTC)},
+					},
+					index.SrcID("c"): {
+						Sidecar: &Content{Created: time.Date(2003, 1, 1, 1, 1, 1, 1, time.UTC)},
+					},
+				},
 			},
-			want: time.Date(2001, 2, 1, 1, 1, 1, 1, time.UTC),
+			want: time.Date(2001, 1, 1, 1, 1, 1, 1, time.UTC),
 		},
 		{
-			desc: "prefers sidecar to inherent",
+			desc: "v0: sidecar with date",
 			m: &Meta{
-				Inherent: Content{Created: time.Date(2001, 1, 1, 1, 1, 1, 1, time.UTC)},
-				Sidecar:  Content{Created: time.Date(2001, 2, 1, 1, 1, 1, 1, time.UTC)},
+				V0Sidecar: Content{Created: time.Date(2001, 2, 1, 1, 1, 1, 1, time.UTC)},
 			},
 			want: time.Date(2001, 2, 1, 1, 1, 1, 1, time.UTC),
 		},
+		{
+			desc: "v0: prefers sidecar to inherent",
+			m: &Meta{
+				Inherent:  Content{Created: time.Date(2001, 1, 1, 1, 1, 1, 1, time.UTC)},
+				V0Sidecar: Content{Created: time.Date(2002, 1, 1, 1, 1, 1, 1, time.UTC)},
+			},
+			want: time.Date(2002, 1, 1, 1, 1, 1, 1, time.UTC),
+		},
 	}
 	for _, tt := range tests {
 		got := tt.m.DateCreated()
 		if got, want := got, tt.want; !reflect.DeepEqual(got, want) {
-			t.Errorf("%q Meta.DateCreated()\ngot  %#v\nwant %#v", tt.desc, got, want)
+			t.Errorf("%q Meta.DateCreated()\ngot  %s\nwant %s", tt.desc, got, want)
 		}
 	}
 }