diff --git a/csl/chicago-author-date.csl b/csl/chicago-author-date.csl
index 4a7565dcb..710c07bf1 100644
--- a/csl/chicago-author-date.csl
+++ b/csl/chicago-author-date.csl
@@ -131,7 +131,6 @@
     <option name="disambiguate-add-year-suffix" value="true"/>
     <option name="disambiguate-add-names" value="true"/>
     <option name="disambiguate-add-givenname" value="true"/>
-    <option name="collapse" value="year"/>
     <layout prefix="(" suffix=")" delimiter="; ">
       <group delimiter=", ">
 	<group delimiter=" ">
diff --git a/csl/harvard1.csl b/csl/harvard1.csl
index a50b78a99..d4f098f1b 100644
--- a/csl/harvard1.csl
+++ b/csl/harvard1.csl
@@ -113,7 +113,6 @@
     <option name="disambiguate-add-year-suffix" value="true"/>
     <option name="disambiguate-add-names" value="true"/>
     <option name="disambiguate-add-givenname" value="true"/>
-    <option name="collapse" value="year"/>
     <layout prefix="(" suffix=")" delimiter="; ">
       <group delimiter=", ">
 	<group delimiter=" ">