diff --git a/history/history-network-test-vectors.md b/history/history-network-test-vectors.md
index 0ab779e6..de1eb9aa 100644
--- a/history/history-network-test-vectors.md
+++ b/history/history-network-test-vectors.md
@@ -127,3 +127,18 @@ content_key = 0x034e61bc0000000000
 content_id = 0x2113990747a85ab39785d21342fa5db1f68acc0011605c0c73f68fc331643dcf
 content_id: U256 = 14960950260935695396511307566164035182676768442501235074589175304147024756175
 ```
+
+#### Ephemeral Block Headers
+
+##### Input Parameters
+```
+block_hash = 0xd1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d
+ancestor_count = 242
+```
+
+##### Expected Output
+```
+content_key = 0x04d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621df2
+content_id = 0xee3af053669ddd2130227b62f899547d6b6cc94f2492e9bbc731025a5ff92d53
+content_id: U256 = 107754593760180144978479156856849717135578675732374967927631096183784899947859
+```