diff --git a/docs/modders/Bonus/Bonus_Types.md b/docs/modders/Bonus/Bonus_Types.md
index 43372cfe0..7648bcd1a 100644
--- a/docs/modders/Bonus/Bonus_Types.md
+++ b/docs/modders/Bonus/Bonus_Types.md
@@ -775,17 +775,21 @@ Determines how many times per combat affected creature can cast its targeted spe
 
 - subtype - spell id, eg. spell.iceBolt
 - value - chance (percent)
-- additional info - \[X, Y\]
+- additional info - \[X, Y, Z\]
     - X - spell level
     - Y = 0 - all attacks, 1 - shot only, 2 - melee only
+    - Z (optional) - layer for multiple SPELL_AFTER_ATTACK bonuses and multi-turn casting. Empty or value less than 0 = not participating in layering.
+  When enabled - spells from specific layer will not be cast until target has all spells from previous layer on him. Spell from last layer is on repeat if none of spells on lower layers expired.
 
 ### SPELL_BEFORE_ATTACK
 
 - subtype - spell id
 - value - chance %
-- additional info - \[X, Y\]
+- additional info - \[X, Y, Z\]
     - X - spell level
     - Y = 0 - all attacks, 1 - shot only, 2 - melee only
+    - Z (optional) - layer for multiple SPELL_BEFORE_ATTACK bonuses and multi-turn casting. Empty or value less than 0 = not participating in layering.
+  When enabled - spells from specific layer will not be cast until target has all spells from previous layer on him. Spell from last layer is on repeat if none of spells on lower layers expired.
 
 ### SPECIFIC_SPELL_POWER 
 
diff --git a/lib/bonuses/BonusEnum.h b/lib/bonuses/BonusEnum.h
index 0839cfb4b..c5f9ad74c 100644
--- a/lib/bonuses/BonusEnum.h
+++ b/lib/bonuses/BonusEnum.h
@@ -57,8 +57,8 @@ class JsonNode;
 	BONUS_NAME(MAGIC_RESISTANCE) /*in % (value)*/		\
 	BONUS_NAME(CHANGES_SPELL_COST_FOR_ALLY) /*in mana points (value) , eg. mage*/ \
 	BONUS_NAME(CHANGES_SPELL_COST_FOR_ENEMY) /*in mana points (value) , eg. pegasus */ \
-	BONUS_NAME(SPELL_AFTER_ATTACK) /* subtype - spell id, value - chance %, addInfo[0] - level, addInfo[1] -> [0 - all attacks, 1 - shot only, 2 - melee only], addInfo[2] -> backup spell layer (default none [-1]) */ \
-	BONUS_NAME(SPELL_BEFORE_ATTACK) /* subtype - spell id, value - chance %, addInfo[0] - level, addInfo[1] -> [0 - all attacks, 1 - shot only, 2 - melee only] */ \
+	BONUS_NAME(SPELL_AFTER_ATTACK) /* subtype - spell id, value - chance %, addInfo[0] - level, addInfo[1] -> [0 - all attacks, 1 - shot only, 2 - melee only], addInfo[2] -> spell layer for multiple SPELL_AFTER_ATTACK bonuses (default none [-1]) */ \
+	BONUS_NAME(SPELL_BEFORE_ATTACK) /* subtype - spell id, value - chance %, addInfo[0] - level, addInfo[1] -> [0 - all attacks, 1 - shot only, 2 - melee only], addInfo[2] -> spell layer for multiple SPELL_BEFORE_ATTACK bonuses (default none [-1]) */ \
 	BONUS_NAME(SPELL_RESISTANCE_AURA) /*eg. unicorns, value - resistance bonus in % for adjacent creatures*/ \
 	BONUS_NAME(LEVEL_SPELL_IMMUNITY) /*creature is immune to all spell with level below or equal to value of this bonus */ \
 	BONUS_NAME(BLOCK_MAGIC_ABOVE) /*blocks casting spells of the level > value */ \
diff --git a/server/battles/BattleActionProcessor.h b/server/battles/BattleActionProcessor.h
index 85585b7e7..39d41eccd 100644
--- a/server/battles/BattleActionProcessor.h
+++ b/server/battles/BattleActionProcessor.h
@@ -46,7 +46,7 @@ class BattleActionProcessor : boost::noncopyable
 	void handleAttackBeforeCasting(const CBattleInfoCallback & battle, bool ranged, const CStack * attacker, const CStack * defender);
 	void handleAfterAttackCasting(const CBattleInfoCallback & battle, bool ranged, const CStack * attacker, const CStack * defender);
 	void attackCasting(const CBattleInfoCallback & battle, bool ranged, BonusType attackMode, const battle::Unit * attacker, const CStack * defender);
-	
+
 	std::set<SpellID> getSpellsForAttackCasting(TConstBonusListPtr spells, const CStack *defender);
 
 	// damage, drain life & fire shield; returns amount of drained life