diff --git a/src/rosbags/typesys/idl.py b/src/rosbags/typesys/idl.py
index b9542272..259f7ce5 100644
--- a/src/rosbags/typesys/idl.py
+++ b/src/rosbags/typesys/idl.py
@@ -253,6 +253,11 @@ class VisitorIDL(Visitor):  # pylint: disable=too-many-public-methods
 
     RULES = parse_grammar(GRAMMAR_IDL)
 
+    def __init__(self):
+        """Initialize."""
+        super().__init__()
+        self.typedefs = {}
+
     def visit_specification(self, children: Any) -> Typesdict:
         """Process start symbol, return only children of modules."""
         children = [x[0] for x in children if x is not None]
diff --git a/src/rosbags/typesys/msg.py b/src/rosbags/typesys/msg.py
index 7242d12a..59739c0f 100644
--- a/src/rosbags/typesys/msg.py
+++ b/src/rosbags/typesys/msg.py
@@ -89,10 +89,11 @@ def normalize_msgtype(name: str) -> str:
     return str(path)
 
 
-def normalize_fieldtype(field: Any, names: List[str]):
+def normalize_fieldtype(typename: str, field: Any, names: List[str]):
     """Normalize field typename.
 
     Args:
+        typename: Type name of field owner.
         field: Field definition.
         names: Valid message names.
 
@@ -111,9 +112,12 @@ def normalize_fieldtype(field: Any, names: List[str]):
     else:
         if name in dct:
             name = dct[name]
+        elif name == 'Header':
+            name = 'std_msgs/msg/Header'
+        elif '/' not in name:
+            name = str(Path(typename).parent / name)
         elif '/msg/' not in name:
-            ptype = Path(name)
-            name = str(ptype.parent / 'msg' / ptype.name)
+            name = str((path := Path(name)).parent / 'msg' / path.name)
         inamedef = (Nodetype.NAME, name)
 
     if namedef[0] == Nodetype.NAME:
@@ -159,9 +163,9 @@ class VisitorMSG(Visitor):
         typelist = [children[0], *[x[1] for x in children[1]]]
         typedict = dict(typelist)
         names = list(typedict.keys())
-        for _, fields in typedict.items():
+        for name, fields in typedict.items():
             for field in fields:
-                normalize_fieldtype(field, names)
+                normalize_fieldtype(name, field, names)
         return typedict
 
     def visit_msgdef(self, children: Any) -> Any:
diff --git a/src/rosbags/typesys/peg.py b/src/rosbags/typesys/peg.py
index 95d1e731..92cc229b 100644
--- a/src/rosbags/typesys/peg.py
+++ b/src/rosbags/typesys/peg.py
@@ -58,10 +58,22 @@ class Rule:
 class RuleLiteral(Rule):
     """Rule to match string literal."""
 
+    def __init__(self, value: Any, rules: Dict[str, Rule], name: Optional[str] = None):
+        """Initialize.
+
+        Args:
+            value: Value of this rule.
+            rules: Grammar containing all rules.
+            name: Name of this rule.
+
+        """
+        super().__init__(value, rules, name)
+        self.value = value[1:-1].replace('\\\'', '\'')
+
     def parse(self, text: str, pos: int) -> Tuple[int, Any]:
         """Apply rule at position."""
-        value: str = self.value[1:-1].replace('\\\'', '\'')
-        if text[pos:].startswith(value):
+        value = self.value
+        if text[pos:pos + len(value)] == value:
             npos = pos + len(value)
             npos = self.skip_ws(text, npos)
             return npos, (self.LIT, value)
@@ -71,10 +83,21 @@ class RuleLiteral(Rule):
 class RuleRegex(Rule):
     """Rule to match regular expression."""
 
+    def __init__(self, value: Any, rules: Dict[str, Rule], name: Optional[str] = None):
+        """Initialize.
+
+        Args:
+            value: Value of this rule.
+            rules: Grammar containing all rules.
+            name: Name of this rule.
+
+        """
+        super().__init__(value, rules, name)
+        self.value = re.compile(value[2:-1], re.M | re.S)
+
     def parse(self, text: str, pos: int) -> Tuple[int, Any]:
         """Apply rule at position."""
-        pattern = re.compile(self.value[2:-1], re.M | re.S)
-        match = pattern.match(text, pos)
+        match = self.value.match(text, pos)
         if not match:
             return -1, []
         npos = self.skip_ws(text, match.span()[1])
@@ -171,7 +194,6 @@ class Visitor:  # pylint: disable=too-few-public-methods
 
     def __init__(self):
         """Initialize."""
-        self.typedefs = {}
 
     def visit(self, tree: Any) -> Any:
         """Visit all nodes in parse tree."""
diff --git a/tests/test_parse.py b/tests/test_parse.py
index 014149ce..d5ea00fe 100644
--- a/tests/test_parse.py
+++ b/tests/test_parse.py
@@ -37,6 +37,11 @@ MSG: test_msgs/Other
 uint64[3] Header
 """
 
+RELSIBLING_MSG = """
+Header header
+Other other
+"""
+
 IDL_LANG = """
 // assign different literals and expressions
 
@@ -122,6 +127,17 @@ def test_parse_multi_msg():
     assert ret['test_msgs/msg/Foo'][2][0][1] == 'uint8'
 
 
+def test_parse_relative_siblings_msg():
+    """Test relative siblings with msg parser."""
+    ret = get_types_from_msg(RELSIBLING_MSG, 'test_msgs/msg/Foo')
+    assert ret['test_msgs/msg/Foo'][0][0][1] == 'std_msgs/msg/Header'
+    assert ret['test_msgs/msg/Foo'][1][0][1] == 'test_msgs/msg/Other'
+
+    ret = get_types_from_msg(RELSIBLING_MSG, 'rel_msgs/msg/Foo')
+    assert ret['rel_msgs/msg/Foo'][0][0][1] == 'std_msgs/msg/Header'
+    assert ret['rel_msgs/msg/Foo'][1][0][1] == 'rel_msgs/msg/Other'
+
+
 def test_parse_idl():
     """Test idl parser."""
     ret = get_types_from_idl(IDL_LANG)