diff --git a/src/Schema.js b/src/Schema.js
index e6f810f..013bf01 100644
--- a/src/Schema.js
+++ b/src/Schema.js
@@ -146,7 +146,7 @@ class Schema {
     setError(key, error, index) {
         if (!this.errors[key]) this.errors[key] = [];
         if (index > -1) {
-            this.errors[key][index] = mergeErrors(error, this.errors[key][index]);
+            this.errors[key][index] = mergeErrors(this.errors[key][index], error);
             return;
         }
         this.errors[key].push(error);
diff --git a/src/helpers.js b/src/helpers.js
index 5deaad6..67af489 100644
--- a/src/helpers.js
+++ b/src/helpers.js
@@ -82,6 +82,12 @@ export const getErrorIndexFromKeys = (keys) => {
 export const mergeErrors = (currentErrors = {}, nextErrors = {}) => {
     const errors = {};
     const errorKeys = new Set();
+    if (typeof nextErrors === 'string') {
+        if (!Array.isArray(currentErrors)) {
+            return [nextErrors];
+        }
+        return [...currentErrors, nextErrors];
+    }
     Object.keys(currentErrors).forEach(key => errorKeys.add(key));
     Object.keys(nextErrors).forEach(key => errorKeys.add(key));
     errorKeys.forEach((key) => {
diff --git a/src/helpers.test.js b/src/helpers.test.js
index 0bc905a..9a887b2 100644
--- a/src/helpers.test.js
+++ b/src/helpers.test.js
@@ -250,5 +250,15 @@ describe('helpers', () => {
             const nextErrors = undefined;
             expect(mergeErrors(currentErrors, nextErrors)).toEqual({});
         });
+        it('should return array with errors if next error is string', () => {
+            const currentErrors = ['foo error'];
+            const nextErrors = 'bar error';
+            expect(mergeErrors(currentErrors, nextErrors)).toEqual(['foo error', 'bar error']);
+        });
+        it('should return array with error if next error is string and current error is undefined', () => {
+            const currentErrors = undefined;
+            const nextErrors = 'bar error';
+            expect(mergeErrors(currentErrors, nextErrors)).toEqual(['bar error']);
+        });
     });
 });