diff --git a/CHANGELOG.md b/CHANGELOG.md
index 26584a1..8a9d8ba 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -21,6 +21,7 @@
 
 - Fix invalid serialization with a duplicated comma when removing a non-edge element from a parsed inline table. ([#486](https://github.com/python-poetry/tomlkit/pull/486))
 - Fix invalid serialization with a duplicated comma when appending or inserting into a comma-first formatted array. ([#499](https://github.com/python-poetry/tomlkit/pull/499))
+- Fix `ParseError` when a sub-table extends the last element of an array of tables after an unrelated table. ([#261](https://github.com/python-poetry/tomlkit/issues/261))
 - Fix unparseable serialization when adding a key to a dotted-key table inside an inline table. ([#500](https://github.com/python-poetry/tomlkit/pull/500))
 - Fix a table replaced by a plain value being serialized inside the preceding table's body when other tables follow; the value now moves before the first table like other root-level values. ([#504](https://github.com/python-poetry/tomlkit/issues/504))
 - Restore `dumps()` rendering mapping-like wrappers around a parsed document (e.g. `dotty_dict`'s `Dotty`) through their delegated `as_string`, preserving the original table order and layout instead of re-encoding through a plain dict — a 0.15.0 regression. ([#482](https://github.com/python-poetry/tomlkit/issues/482))
diff --git a/README.md b/README.md
index 0baf4f8..4a88fd4 100644
--- a/README.md
+++ b/README.md
@@ -26,6 +26,15 @@ Part of the implementation has been adapted, improved and fixed from [Molten](ht
 
 See the [documentation](https://tomlkit.readthedocs.io/) for more information.
 
+## Limitations
+
+`tomlkit` preserves the original layout of a document, with one exception: a
+sub-table that extends an array of tables out of order — for example a
+`[fruit.apple.texture]` header that appears after `[[fruit]]` with an unrelated
+table in between — is normalized into the array's last element when the document
+is re-serialized, rather than kept at its original position. The data is
+preserved; only the physical placement of that sub-table changes.
+
 ## Installation
 
 If you are using [uv](https://docs.astral.sh/uv), you can
diff --git a/tests/test_toml_document.py b/tests/test_toml_document.py
index 1cdfb9c..1b0508b 100644
--- a/tests/test_toml_document.py
+++ b/tests/test_toml_document.py
@@ -239,6 +239,25 @@ def test_document_with_aot_after_sub_tables() -> None:
     assert doc["foo"]["bar"]["tests"][0]["name"] == "Test 1"
 
 
+def test_subtable_of_aot_element_after_other_table() -> None:
+    # A sub-table header that extends the last element of an array of tables
+    # is valid even when an unrelated table appears in between (issue #261).
+    content = """[[fruit]]
+apple.color = "red"
+
+[potato]
+
+[fruit.apple.texture]
+smooth = true
+"""
+
+    doc = parse(content)
+
+    assert doc["fruit"][0]["apple"]["color"] == "red"
+    assert doc["fruit"][0]["apple"]["texture"]["smooth"] is True
+    assert doc["potato"] == {}
+
+
 def test_document_with_new_sub_table_after_other_table() -> None:
     content = """[foo]
 name = "Bar"
diff --git a/tomlkit/container.py b/tomlkit/container.py
index 75e0901..0a96089 100644
--- a/tomlkit/container.py
+++ b/tomlkit/container.py
@@ -260,6 +260,16 @@ def append(
                     return self
                 elif isinstance(current, AoT):
                     if not item.is_aot_element():
+                        if item.is_super_table() and len(current.body):
+                            # A sub-table header such as `[fruit.apple.texture]`
+                            # appearing after the array `[[fruit]]` (possibly with
+                            # unrelated tables in between) extends the last element
+                            # of the array, per the TOML spec.
+                            last = current[-1]
+                            for k, v in item.value.body:
+                                last.value.append(k, v)
+
+                            return self
                         # Tried to define a table after an AoT with the same name.
                         raise KeyAlreadyPresent(key)