diff --git a/df.personality.xml b/df.personality.xml
index f19bf9fec..ae398184a 100644
--- a/df.personality.xml
+++ b/df.personality.xml
@@ -1412,8 +1412,20 @@
         <int32_t name="need_level" original-name='severity' comment='how fast focus_level decreases when it below 0'/>
     </struct-type>
 
-    -- Unused: CIRCUMSTANCE_FLAG_*
-    -- Unused: circumstancest
+    <bitfield-type type-name='circumstance_flag' base-type='uint32_t'> bay12: CIRCUMSTANCE_FLAG_*
+        <flag-bit name='HAPPENED_IN_PAST'/>
+    </bitfield-type>
+
+    <struct-type type-name='circumstancest' comment='not used by DFHack, included for disassembly'>
+        <enum type-name='unit_thought_type' name='type'/>
+        <int32_t name='id'/>
+        <int32_t name='value'/>
+        <int32_t name='simple_care_eval'/>
+        <bitfield base-type='uint32_t' type-name='circumstance_flag' name='flag'/>
+        <pointer name='ptr' comment='unioned with incidentst *in_ptr'/>
+        <pointer type-name='unit_soul' name='soul'/>
+        <pointer type-name='historical_figure' name='experiencer_hf'/>
+    </struct-type>
 
     <struct-type type-name='soul_personality_changest'>
         <static-array type-name='int16_t' name='traits' original-name='nfacet_shift' index-enum='personality_facet_type'/>