diff --git a/tableauserverclient/__init__.py b/tableauserverclient/__init__.py
index 819cfcfa6..4e148b327 100644
--- a/tableauserverclient/__init__.py
+++ b/tableauserverclient/__init__.py
@@ -1,5 +1,11 @@
 from tableauserverclient.bin._version import get_versions
-from tableauserverclient.namespace import NEW_NAMESPACE as DEFAULT_NAMESPACE
+
+# Inlined as a string literal (rather than imported from server.server) so
+# loading `tableauserverclient` doesn't force the full server + endpoint
+# import graph to load just to read a constant. Kept in sync with the
+# NAMESPACE constant defined in tableauserverclient/server/server.py.
+DEFAULT_NAMESPACE = "http://tableau.com/api"
+
 from tableauserverclient.models import (
     AuthFederationConnectorItem,
     AuthFederationItem,
diff --git a/tableauserverclient/namespace.py b/tableauserverclient/namespace.py
deleted file mode 100644
index 2b5e5b2b5..000000000
--- a/tableauserverclient/namespace.py
+++ /dev/null
@@ -1,40 +0,0 @@
-import re
-
-from defusedxml.ElementTree import fromstring
-
-OLD_NAMESPACE = "http://tableausoftware.com/api"
-NEW_NAMESPACE = "http://tableau.com/api"
-NAMESPACE_RE = re.compile(r"\{(.*?)\}")
-
-
-class UnknownNamespaceError(Exception):
-    """Raised when an XML response contains an unrecognized Tableau API namespace."""
-
-
-class Namespace:
-    """Detects and stores the Tableau REST API XML namespace from server responses."""
-
-    def __init__(self):
-        self._namespace = {"t": NEW_NAMESPACE}
-        self._detected = False
-
-    def __call__(self):
-        return self._namespace
-
-    def detect(self, xml):
-        """Detect the XML namespace from raw response bytes, updating the stored namespace on first call. Raises UnknownNamespaceError if the namespace is not a recognized Tableau REST API namespace."""
-        if self._detected:
-            return
-
-        if not xml.startswith(b"<?xml"):
-            return  # Not an xml file, don't detect anything
-
-        root = fromstring(xml)
-        matches = NAMESPACE_RE.match(root.tag)
-        if matches:
-            detected_ns = matches.group(1)
-            if detected_ns in (OLD_NAMESPACE, NEW_NAMESPACE):
-                self._namespace = {"t": detected_ns}
-                self._detected = True
-            else:
-                raise UnknownNamespaceError(detected_ns)
diff --git a/tableauserverclient/server/endpoint/auth_endpoint.py b/tableauserverclient/server/endpoint/auth_endpoint.py
index 110d38a18..28f30fb46 100644
--- a/tableauserverclient/server/endpoint/auth_endpoint.py
+++ b/tableauserverclient/server/endpoint/auth_endpoint.py
@@ -152,7 +152,6 @@ def switch_site(self, site_item: "SiteItem") -> contextmgr:
                 return Auth.contextmgr(self.sign_out)
             else:
                 raise e
-        self.parent_srv._namespace.detect(server_response.content)
         self._check_status(server_response, url)
         parsed_response = fromstring(server_response.content)
         site_id = parsed_response.find(".//t:site", namespaces=self.parent_srv.namespace).get("id", None)
diff --git a/tableauserverclient/server/endpoint/endpoint.py b/tableauserverclient/server/endpoint/endpoint.py
index 10d3cba84..fa9540534 100644
--- a/tableauserverclient/server/endpoint/endpoint.py
+++ b/tableauserverclient/server/endpoint/endpoint.py
@@ -181,9 +181,6 @@ def _make_request(
         # BE CAREFUL WHEN SHARING THESE RESULTS - MAY CONTAIN YOUR SENSITIVE DATA
         # logger.debug(loggable_response)
 
-        if content_type == "application/xml":
-            self.parent_srv._namespace.detect(server_response.content)
-
         return server_response
 
     def _follow_redirect_if_any(
diff --git a/tableauserverclient/server/server.py b/tableauserverclient/server/server.py
index 853bdea68..fc5cdb976 100644
--- a/tableauserverclient/server/server.py
+++ b/tableauserverclient/server/server.py
@@ -51,7 +51,6 @@
     EndpointUnavailableError,
 )
 from tableauserverclient.server.endpoint.exceptions import NotSignedInError
-from tableauserverclient.namespace import Namespace
 
 _PRODUCT_TO_REST_VERSION = {
     "10.0": "2.3",
@@ -64,6 +63,11 @@
 minimum_supported_server_version = "2.3"
 default_server_version = "2.4"  # first version that dropped the legacy auth endpoint
 
+# The REST API has used the "http://tableau.com/api" XML namespace since Tableau
+# Server 8.3 (2015). Callers on older servers are unsupported.
+NAMESPACE = "http://tableau.com/api"
+_NAMESPACE_MAP = {"t": NAMESPACE}
+
 
 class _AuthState(NamedTuple):
     """
@@ -224,7 +228,6 @@ def __init__(self, server_address, use_server_version=False, http_options=None,
         self.data_acceleration_report = DataAccelerationReport(self)
         self.data_alerts = DataAlerts(self)
         self.fileuploads = Fileuploads(self)
-        self._namespace = Namespace()
         self.flow_runs = FlowRuns(self)
         self.metrics = Metrics(self)
         self.custom_views = CustomViews(self)
@@ -381,7 +384,7 @@ def baseurl(self):
 
     @property
     def namespace(self):
-        return self._namespace()
+        return dict(_NAMESPACE_MAP)
 
     @property
     def auth_token(self):
diff --git a/test/test_namespace.py b/test/test_namespace.py
new file mode 100644
index 000000000..2b4a891cc
--- /dev/null
+++ b/test/test_namespace.py
@@ -0,0 +1,20 @@
+import tableauserverclient as TSC
+from tableauserverclient.server import server as server_module
+
+
+def test_default_namespace_matches_server_namespace() -> None:
+    # TSC.DEFAULT_NAMESPACE is a literal in __init__.py (importing it from server.py is circular).
+    assert TSC.DEFAULT_NAMESPACE == server_module.NAMESPACE
+
+
+def test_server_namespace_maps_t_prefix() -> None:
+    server = TSC.Server("http://test", False)
+    assert server.namespace == {"t": TSC.DEFAULT_NAMESPACE}
+
+
+def test_server_namespace_is_a_copy() -> None:
+    server = TSC.Server("http://test", False)
+    server.namespace["t"] = "mutated"
+    server.namespace["x"] = "extra"
+    assert server.namespace == {"t": TSC.DEFAULT_NAMESPACE}
+    assert TSC.Server("http://other", False).namespace == {"t": TSC.DEFAULT_NAMESPACE}