diff --git a/cardano-api/internal/Cardano/Api/Eon/AllegraEraOnwards.hs b/cardano-api/internal/Cardano/Api/Eon/AllegraEraOnwards.hs
index e7adbc0979..1bc8c80856 100644
--- a/cardano-api/internal/Cardano/Api/Eon/AllegraEraOnwards.hs
+++ b/cardano-api/internal/Cardano/Api/Eon/AllegraEraOnwards.hs
@@ -111,7 +111,7 @@ allegraEraOnwardsToShelleyBasedEra = \case
   AllegraEraOnwardsBabbage -> ShelleyBasedEraBabbage
   AllegraEraOnwardsConway -> ShelleyBasedEraConway
 
-class IsAllegraBasedEra era where
+class IsShelleyBasedEra era => IsAllegraBasedEra era where
   allegraBasedEra :: AllegraEraOnwards era
 
 instance IsAllegraBasedEra AllegraEra where
diff --git a/cardano-api/internal/Cardano/Api/Eon/AlonzoEraOnwards.hs b/cardano-api/internal/Cardano/Api/Eon/AlonzoEraOnwards.hs
index 150f9a6ca2..b4997b90e1 100644
--- a/cardano-api/internal/Cardano/Api/Eon/AlonzoEraOnwards.hs
+++ b/cardano-api/internal/Cardano/Api/Eon/AlonzoEraOnwards.hs
@@ -17,6 +17,7 @@ module Cardano.Api.Eon.AlonzoEraOnwards
   )
 where
 
+import           Cardano.Api.Eon.MaryEraOnwards
 import           Cardano.Api.Eon.ShelleyBasedEra
 import           Cardano.Api.Eras.Core
 import           Cardano.Api.Modes
@@ -119,7 +120,7 @@ alonzoEraOnwardsToShelleyBasedEra = \case
   AlonzoEraOnwardsBabbage -> ShelleyBasedEraBabbage
   AlonzoEraOnwardsConway -> ShelleyBasedEraConway
 
-class IsAlonzoBasedEra era where
+class IsMaryBasedEra era => IsAlonzoBasedEra era where
   alonzoBasedEra :: AlonzoEraOnwards era
 
 instance IsAlonzoBasedEra AlonzoEra where
diff --git a/cardano-api/internal/Cardano/Api/Eon/BabbageEraOnwards.hs b/cardano-api/internal/Cardano/Api/Eon/BabbageEraOnwards.hs
index 979e144f18..32fe98c4b4 100644
--- a/cardano-api/internal/Cardano/Api/Eon/BabbageEraOnwards.hs
+++ b/cardano-api/internal/Cardano/Api/Eon/BabbageEraOnwards.hs
@@ -17,6 +17,7 @@ module Cardano.Api.Eon.BabbageEraOnwards
   )
 where
 
+import           Cardano.Api.Eon.AlonzoEraOnwards
 import           Cardano.Api.Eon.ShelleyBasedEra
 import           Cardano.Api.Eras.Core
 import           Cardano.Api.Modes
@@ -113,7 +114,7 @@ babbageEraOnwardsToShelleyBasedEra = \case
   BabbageEraOnwardsBabbage -> ShelleyBasedEraBabbage
   BabbageEraOnwardsConway -> ShelleyBasedEraConway
 
-class IsBabbageBasedEra era where
+class IsAlonzoBasedEra era => IsBabbageBasedEra era where
   babbageBasedEra :: BabbageEraOnwards era
 
 instance IsBabbageBasedEra BabbageEra where
diff --git a/cardano-api/internal/Cardano/Api/Eon/ConwayEraOnwards.hs b/cardano-api/internal/Cardano/Api/Eon/ConwayEraOnwards.hs
index d991fdfbd3..f8d5210925 100644
--- a/cardano-api/internal/Cardano/Api/Eon/ConwayEraOnwards.hs
+++ b/cardano-api/internal/Cardano/Api/Eon/ConwayEraOnwards.hs
@@ -120,7 +120,7 @@ conwayEraOnwardsToBabbageEraOnwards :: ConwayEraOnwards era -> BabbageEraOnwards
 conwayEraOnwardsToBabbageEraOnwards = \case
   ConwayEraOnwardsConway -> BabbageEraOnwardsConway
 
-class IsConwayBasedEra era where
+class IsBabbageBasedEra era => IsConwayBasedEra era where
   conwayBasedEra :: ConwayEraOnwards era
 
 instance IsConwayBasedEra ConwayEra where
diff --git a/cardano-api/internal/Cardano/Api/Eon/MaryEraOnwards.hs b/cardano-api/internal/Cardano/Api/Eon/MaryEraOnwards.hs
index 3f59847306..fd4f1ab85c 100644
--- a/cardano-api/internal/Cardano/Api/Eon/MaryEraOnwards.hs
+++ b/cardano-api/internal/Cardano/Api/Eon/MaryEraOnwards.hs
@@ -17,6 +17,7 @@ module Cardano.Api.Eon.MaryEraOnwards
   )
 where
 
+import           Cardano.Api.Eon.AllegraEraOnwards
 import           Cardano.Api.Eon.ShelleyBasedEra
 import           Cardano.Api.Eras.Core
 import           Cardano.Api.Modes
@@ -111,7 +112,7 @@ maryEraOnwardsToShelleyBasedEra = \case
   MaryEraOnwardsBabbage -> ShelleyBasedEraBabbage
   MaryEraOnwardsConway -> ShelleyBasedEraConway
 
-class IsMaryBasedEra era where
+class IsAllegraBasedEra era => IsMaryBasedEra era where
   maryBasedEra :: MaryEraOnwards era
 
 instance IsMaryBasedEra MaryEra where