diff --git a/cheuph/render/__init__.py b/cheuph/render/__init__.py
new file mode 100644
index 0000000..440d10c
--- /dev/null
+++ b/cheuph/render/__init__.py
@@ -0,0 +1,8 @@
+from .element import *
+from .markup import *
+from .tree_display import *
+
+__all__ = []
+__all__ += element.__all__
+__all__ += markup.__all__
+__all__ += tree_display.__all__
diff --git a/cheuph/render/element.py b/cheuph/render/element.py
new file mode 100644
index 0000000..6d71c99
--- /dev/null
+++ b/cheuph/render/element.py
@@ -0,0 +1,29 @@
+from typing import Hashable, List
+
+from .markup import AttributedText
+
+__all__ = ["Id", "Element", "ElementSupply", "RenderedElement"]
+
+Id = Hashable
+
+class Element:
+    pass
+
+class ElementSupply:
+    pass
+
+class RenderedElement:
+    def __init__(self,
+            element: Element,
+            rendered: List[AttributedText],
+            ) -> None:
+        self._element = element
+        self._lines = rendered
+
+    @property
+    def element(self) -> Element:
+        return self._element
+
+    @property
+    def height(self) -> int:
+        return len(self._lines)
diff --git a/cheuph/render/markup.py b/cheuph/render/markup.py
new file mode 100644
index 0000000..68e19cb
--- /dev/null
+++ b/cheuph/render/markup.py
@@ -0,0 +1,286 @@
+from typing import Any, Dict, Iterable, List, Optional, Tuple, Union
+
+__all__ = ["Attributes", "Chunk", "AttributedText"]
+
+Attributes = Dict[str, Any]
+
+
+# TODO remove empty Chunks in join_chunks
+class Chunk:
+    @staticmethod
+    def join_chunks(chunks: List["Chunk"]) -> List["Chunk"]:
+        if not chunks:
+            return []
+
+        new_chunks: List[Chunk] = []
+
+        current_chunk = chunks[0]
+        for chunk in chunks[1:]:
+            joined_chunk = current_chunk._join(chunk)
+
+            if joined_chunk is None:
+                new_chunks.append(current_chunk)
+                current_chunk = chunk
+            else:
+                current_chunk = joined_chunk
+
+        new_chunks.append(current_chunk)
+
+        return new_chunks
+
+    # Common special methods
+
+    def __init__(self,
+            text: str,
+            attributes: Attributes = {},
+            ) -> None:
+        self._text = text
+        self._attributes = dict(attributes)
+
+    def __str__(self) -> str:
+        return self.text
+
+    def __repr__(self) -> str:
+        return f"Chunk({self.text!r}, {self._attributes!r})"
+
+    # Uncommon special methods
+
+    def __getitem__(self, key: Union[int, slice]) -> "Chunk":
+        return Chunk(self.text[key], self._attributes)
+
+    def __len__(self) -> int:
+        return len(self.text)
+
+    # Properties
+
+    @property
+    def text(self) -> str:
+        return self._text
+
+    @property
+    def attributes(self) -> Attributes:
+        return dict(self._attributes)
+
+    # Private methods
+
+    def _join(self, chunk: "Chunk") -> Optional["Chunk"]:
+        if self._attributes == chunk._attributes:
+            return Chunk(self.text + chunk.text, self._attributes)
+
+        return None
+
+    # Public methods
+
+    def get(self, name: str, default: Any = None) -> Any:
+        return self.attributes.get(name, default)
+
+    def set(self, name: str, value: Any) -> "Chunk":
+        new_attributes = dict(self._attributes)
+        new_attributes[name] = value
+        return Chunk(self.text, new_attributes)
+
+    def remove(self, name: str) -> "Chunk":
+        new_attributes = dict(self._attributes)
+
+        # This removes the value with that key, if it exists, and does nothing
+        # if it doesn't exist. (Since we give a default value, no KeyError is
+        # raised if the key isn't found.)
+        new_attributes.pop(name, None)
+
+        return Chunk(self.text, new_attributes)
+
+
+class AttributedText:
+    """
+    Objects of this class are immutable and behave str-like. Supported
+    operations are len, + and splicing.
+    """
+
+    @classmethod
+    def from_chunks(cls, chunks: Iterable[Chunk]) -> "AttributedText":
+        new = cls()
+        new._chunks = Chunk.join_chunks(list(chunks))
+        return new
+
+    # Common special methods
+
+    def __init__(self, text: Optional[str] = None) -> None:
+        self._chunks: List[Chunk] = []
+        if text is not None:
+            self._chunks.append(Chunk(text))
+
+    def __str__(self) -> str:
+        return self.text
+
+    def __repr__(self) -> str:
+        return f"AttributedText.from_chunks({self._chunks!r})"
+
+    # Uncommon special methods
+
+    def __add__(self, other: "AttributedText") -> "AttributedText":
+        return AttributedText.from_chunks(self._chunks + other._chunks)
+
+    def __getitem__(self, key: Union[int, slice]) -> "AttributedText":
+        chunks: List[Chunk]
+
+        if isinstance(key, slice):
+            chunks = Chunk.join_chunks(self._slice(key))
+        else:
+            chunks = [self._at(key)]
+
+        return AttributedText.from_chunks(chunks)
+
+    def __len__(self) -> int:
+        return sum(map(len, self._chunks))
+
+    # Properties
+
+    @property
+    def text(self) -> str:
+        return "".join(chunk.text for chunk in self._chunks)
+
+    @property
+    def chunks(self) -> List[Chunk]:
+        return list(self._chunks)
+
+    # Private methods
+
+    def _at(self, key: int) -> Chunk:
+        if key < 0:
+            key = len(self) + key
+
+        pos = 0
+        for chunk in self._chunks:
+            chunk_key = key - pos
+
+            if 0 <= chunk_key < len(chunk):
+                return chunk[chunk_key]
+
+            pos += len(chunk)
+
+        # We haven't found the chunk
+        raise KeyError
+
+    def _slice(self, key: slice) -> List[Chunk]:
+        start, stop, step = key.start, key.stop, key.step
+
+        if start is None:
+            start = 0
+        elif start < 0:
+            start = len(self) + start
+
+        if stop is None:
+            stop = len(self)
+        elif stop < 0:
+            stop = len(self) + stop
+
+        pos = 0 # cursor position
+        resulting_chunks = []
+
+        for chunk in self._chunks:
+            chunk_start = start - pos
+            chunk_stop = stop - pos
+
+            offset: Optional[int] = None
+            if step is not None:
+                offset = (start - pos) % step
+
+            if chunk_stop <= 0 or chunk_start >= len(chunk):
+                pass
+            elif chunk_start < 0 and chunk_stop > len(chunk):
+                resulting_chunks.append(chunk[offset::step])
+            elif chunk_start < 0:
+                resulting_chunks.append(chunk[offset:chunk_stop:step])
+            elif chunk_stop > len(chunk):
+                resulting_chunks.append(chunk[chunk_start::step])
+            else:
+                resulting_chunks.append(chunk[chunk_start:chunk_stop:step])
+
+            pos += len(chunk)
+
+        return resulting_chunks
+
+    # Public methods
+
+    def at(self, pos: int) -> Attributes:
+        return self._at(pos).attributes
+
+    def get(self,
+            pos: int,
+            name: str,
+            default: Any = None,
+            ) -> Any:
+        return self._at(pos).get(name, default)
+
+    # "find all separate blocks with this property"
+    def find_all(self, name: str) -> List[Tuple[Any, int, int]]:
+        blocks = []
+        pos = 0
+        block = None
+
+        for chunk in self._chunks:
+            if name in chunk.attributes:
+                attribute = chunk.attributes[name]
+                start = pos
+                stop = pos + len(chunk)
+
+                if block is None:
+                    block = (attribute, start, stop)
+                    continue
+
+                block_attr, block_start, _ = block
+
+                if block_attr == attribute:
+                    block = (attribute, block_start, stop)
+                else:
+                    blocks.append(block)
+                    block = (attribute, start, stop)
+
+            pos += len(chunk)
+
+        if block is not None:
+            blocks.append(block)
+
+        return blocks
+
+    def set(self,
+            name: str,
+            value: Any,
+            start: Optional[int] = None,
+            stop: Optional[int] = None,
+            ) -> "AttributedText":
+        if start is None and stop is None:
+            chunks = (chunk.set(name, value) for chunk in self._chunks)
+            return AttributedText.from_chunks(chunks)
+        elif start is None:
+            return self[:stop].set(name, value) + self[stop:]
+        elif stop is None:
+            return self[:start] + self[start:].set(name, value)
+        elif start > stop:
+            # set value everywhere BUT the specified interval
+            return self.set(name, value, stop=stop).set(name, value, start=start)
+        else:
+            middle = self[start:stop].set(name, value)
+            return self[:start] + middle + self[stop:]
+
+    def set_at(self, name: str, value: Any, pos: int) -> "AttributedText":
+        return self.set(name, value, pos, pos)
+
+    def remove(self,
+            name: str,
+            start: Optional[int] = None,
+            stop: Optional[int] = None,
+            ) -> "AttributedText":
+        if start is None and stop is None:
+            chunks = (chunk.remove(name) for chunk in self._chunks)
+            return AttributedText.from_chunks(chunks)
+        elif start is None:
+            return self[:stop].remove(name) + self[stop:]
+        elif stop is None:
+            return self[:start] + self[start:].remove(name)
+        elif start > stop:
+            # remove value everywhere BUT the specified interval
+            return self.remove(name, stop=stop).remove(name, start=start)
+        else:
+            middle = self[start:stop].remove(name)
+            return self[:start] + middle + self[stop:]
diff --git a/cheuph/render/tree_display.py b/cheuph/render/tree_display.py
new file mode 100644
index 0000000..3aa1da8
--- /dev/null
+++ b/cheuph/render/tree_display.py
@@ -0,0 +1,126 @@
+import collections
+from typing import Any, Deque, Optional, Set
+
+from .element import ElementSupply, Id, RenderedElement
+
+__all__ = ["TreeDisplay"]
+
+class TreeDisplay:
+    def __init__(self,
+            supply: ElementSupply,
+            width: int,
+            height: int,
+            ) -> None:
+        self._width = width
+        self._height = height
+
+        self._root_id: Optional[Id] = None
+        self._anchor_id: Optional[Id] = None
+        self._cursor_id: Optional[Id] = None
+
+        self._anchor_offset: int = 0
+        self._horizontal_offset: int = 0
+
+        # Object references
+        self._supply = supply
+        self._rendered: Optional[TreeList]
+        self._folded: Set[Id] = set()
+
+    def resize(self, width: int, height: int):
+        # TODO maybe empty _rendered/invalidate caches etc.?
+        self._width = width
+        self._height = height
+
+    def render(self):
+        # Steps:
+        #
+        # 1. Find and render anchor's branch to TreeList
+        # 2. Render above and below the branch until the screen is full (with
+        #    the specified anchor offset)
+        #   2.1. Keep the TreeList for later things like scrolling
+        # 3. Cut out the visible lines and messages
+        # 4. Cut out the visible parts horizontally (self._horizontal_offset)
+        #   4.1. Keep the result for later reference (mouse clicks)
+        # 5. Convert the result to plain text and draw it in the curses window
+        #
+        # Not happy with these steps yet. Scrolling, checking if the cursor is
+        # in view, switching anchors etc. still feel weird.
+        #
+        # TODO Add the above into the TreeDisplay model.
+
+        if self._anchor_id is None:
+            return # TODO draw empty screen
+
+
+        if self._root_id is None:
+            ancestor_id = self._supply.get_furthest_ancestor_id(
+                    self._anchor_id)
+        else:
+            ancestor_id = self._root_id
+
+        ancestor_tree = self._render_tree(self._supply.get_tree(ancestor_id))
+
+        self._rendered = TreeList(ancestor_tree, self._anchor_id)
+        self._rendered.offset_by(self._anchor_offset)
+
+        if self._root_id is None:
+            self._fill_screen_upwards()
+            self._fill_screen_downwards()
+
+    def _render_tree(self, tree: Element, depth=0):
+        elements: List[RenderedElement] = []
+
+        highlighted = tree.id == self._cursor_id
+        folded = tree.id in self._folded
+
+        elements.append(tree.render(depth=depth, highlighted=highlighted,
+            folded=folded))
+
+        if not folded:
+            for child in tree.children:
+                elements.extend(self._render_tree(child, depth=depth+1))
+
+        return elements
+
+    def _fill_screen_upwards(self):
+        while True:
+            if self._rendered.upper_offset <= 0:
+                break
+
+            above_tree_id = self._supply.get_previous_id(
+                    self._rendered.upper_tree_id)
+
+            if above_tree_id is None:
+                break
+
+            above_tree = self._supply.get_tree(above_tree_id)
+            self._rendered.add_above(self._render_tree(above_tree))
+
+    def _fill_screen_downwards(self):
+        """
+        Eerily similar to _fill_screen_upwards()...
+        """
+
+        while True:
+            if self._rendered.lower_offset >= self._height - 1:
+                break
+
+            below_tree_id = self._supply.get_next_id(
+                    self._rendered.lower_tree_id)
+
+            if below_tree_id is None:
+                break
+
+            below_tree = self._supply.get_tree(below_tree_id)
+            self._rendered.add_below(self._render_tree(below_tree))
+
+    def draw_to(self, window: Any):
+        pass
+
+# Terminology:
+#
+# root
+# ancestor
+# parent
+# sibling
+# child
diff --git a/cheuph/render/tree_list.py b/cheuph/render/tree_list.py
new file mode 100644
index 0000000..367fdf1
--- /dev/null
+++ b/cheuph/render/tree_list.py
@@ -0,0 +1,103 @@
+from .element import Id, RenderedElement
+
+__all__ = ["TreeList"]
+
+class TreeList:
+    def __init__(self,
+            tree: List[RenderedElement],
+            anchor_id: Id,
+            ) -> None:
+        self._deque = collections.deque()
+
+        self._anchor_id = anchor_id
+
+        # The offsets can be thought of as the index of a line relative to the
+        # anchor's first line.
+        #
+        # The upper offset is the index of the uppermost message's first line.
+        # upper_offset <= 0.
+        #
+        # The lower offset is the index of the lowermost message's LAST line.
+        # lower_offset >= 0.
+        self._upper_offset: Int
+        self._lower_offset: Int
+
+        # The upper and lower tree ids are the ids of the uppermost or
+        # lowermost tree added to the TreeList. They can be used to request the
+        # previous or next tree from an ElementSupply.
+        self._upper_tree_id: Id
+        self._lower_tree_id: Id
+
+        self._add_first_tree(tree)
+
+    @property
+    def upper_offset(self) -> Int:
+        return self._upper_offset
+
+    @property
+    def lower_offset(self) -> Int:
+        return self._lower_offset
+
+    @property
+    def upper_tree_id(self) -> Id:
+        return self._upper_tree_id
+
+    @property
+    def lower_tree_id(self) -> Id:
+        return self._lower_tree_id
+
+    def _add_first_tree(self, tree: List[RenderedElement]) -> None:
+        if len(tree) == 0:
+            raise ValueError("The tree must contain at least one element")
+
+        tree_id = tree[0].element.id
+        self._upper_tree_id = tree_id
+        self._lower_tree_id = tree_id
+
+        offset = 0
+        found_anchor = False
+
+        for rendered in elements:
+            if rendered.element.id == anchor_id:
+                found_anchor = True
+                self._upper_offset = -offset
+
+            offset += rendered.height
+
+        if not found_anchor:
+            raise ValueError("The initial tree must contain the anchor")
+
+        # Subtracting 1 because the lower offset is the index of the lowermost
+        # message's last line, not the first line of a hypothetical message
+        # below that.
+        self._lower_offset = offset - 1
+
+    def add_above(self, tree: List[RenderedElement]) -> None:
+        if len(tree) == 0:
+            raise ValueError("The tree must contain at least one element")
+
+        self._upper_tree_id = tree[0].element.id
+
+        for rendered in reversed(tree):
+            self._deque.appendleft(rendered)
+            self._upper_offset -= rendered.height
+
+        # Alternative to the above for loop
+        #delta = sum(map(lambda r: r.height, tree))
+        #self._upper_offset -= delta
+        #self._deque.extendLeft(reversed(tree))
+
+    def add_below(self, tree: List[RenderedElement]) -> None:
+        if len(tree) == 0:
+            raise ValueError("The tree must contain at least one element")
+
+        self._lower_tree_id = tree[0].element.id
+
+        for rendered in tree:
+            self._deque.append(rendered)
+            self._lower_offset += rendered.height
+
+        # Alternative to the above for loop
+        #delta = sum(map(lambda r: r.height, tree))
+        #self._lower_offset += delta
+        #self._deque.extend(tree)