diff --git a/i18n.js b/i18n.js
index edf9af2d..68d9735c 100644
--- a/i18n.js
+++ b/i18n.js
@@ -54,6 +54,7 @@ module.exports = (function() {
     logDebugFn,
     logErrorFn,
     logWarnFn,
+    preserveLegacyCase,
     objectNotation,
     prefix,
     queryParameter,
@@ -147,6 +148,9 @@ module.exports = (function() {
     logWarnFn = (typeof opt.logWarnFn === 'function') ? opt.logWarnFn : warn;
     logErrorFn = (typeof opt.logErrorFn === 'function') ? opt.logErrorFn : error;
 
+    preserveLegacyCase = (typeof opt.preserveLegacyCase === 'undefined') ?
+      true : opt.preserveLegacyCase;
+
     // when missing locales we try to guess that from directory
     opt.locales = opt.locales || guessLocales(directory);
 
@@ -659,7 +663,12 @@ module.exports = (function() {
         var urlObj = url.parse(request.url, true);
         if (urlObj.query[queryParameter]) {
           logDebug('Overriding locale from query: ' + urlObj.query[queryParameter]);
-          request.language = urlObj.query[queryParameter].toLowerCase();
+          request.language = urlObj.query[queryParameter];
+
+          if (preserveLegacyCase) {
+            request.language = request.language.toLowerCase();
+          }
+
           return i18n.setLocale(request, request.language);
         }
       }
@@ -1175,4 +1184,4 @@ module.exports = (function() {
 
   return i18n;
 
-}());
\ No newline at end of file
+}());
diff --git a/test/i18n.configureCookiename.js b/test/i18n.configureCookiename.js
index f91dd9ee..7044b0b3 100644
--- a/test/i18n.configureCookiename.js
+++ b/test/i18n.configureCookiename.js
@@ -2,7 +2,7 @@ var i18n = require('../i18n'),
   should = require("should"),
   path = require("path");
 
-describe('Locale switching should work queryParameter', function() {
+describe('Locale switching should work when set via cookie', function() {
 
   var req;
   var res;
diff --git a/test/i18n.configureLocales.js b/test/i18n.configureLocales.js
index dc5aba7e..67c63f0d 100644
--- a/test/i18n.configureLocales.js
+++ b/test/i18n.configureLocales.js
@@ -3,7 +3,7 @@ var i18n = require('../i18n'),
   fs = require('fs'),
   path = require('path');
 
-describe('locals configuration', function() {
+describe('locales configuration', function() {
 
   it('omitting it should read all directory contents', function(done) {
     var directory = path.resolve(__dirname + '/../locales');
@@ -89,4 +89,5 @@ describe('locals configuration', function() {
 
     done();
   });
-});
\ No newline at end of file
+
+});
diff --git a/test/i18n.verifyLocaleSelectionMethods.js b/test/i18n.verifyLocaleSelectionMethods.js
new file mode 100644
index 00000000..2d4f9b49
--- /dev/null
+++ b/test/i18n.verifyLocaleSelectionMethods.js
@@ -0,0 +1,69 @@
+var i18n = require('../i18n'),
+  should = require("should");
+
+describe('when configuring selected locale', function () {
+  var res;
+
+  function setByQueryParam(i18n, locale) {
+    var req = {
+      request: 'GET /test?lang=' + locale,
+      url: '/test?lang=' + locale
+    };
+    i18n.init(req, res);
+    return i18n.getLocale(req);
+  };
+
+  function setByCookie(i18n, locale) {
+    var req = {
+      request: 'GET /test',
+      url: '/test',
+      cookies:{
+        'languageCookie': locale
+      }
+    };
+
+    i18n.init(req, res);
+    return i18n.getLocale(req);
+  };
+
+  function setByHeader(i18n, locale) {
+    var req = {
+      request: 'GET /test',
+      url: '/test',
+      headers: {
+        'accept-language': locale
+      }
+    };
+    i18n.init(req, res);
+    return i18n.getLocale(req);
+  };
+
+  beforeEach(function () {
+    res = { locals: {} };
+    i18n.configure({
+      locales: ['de-AT', 'de-DE', 'en-GB', 'tr-TR', 'en-US', 'en'],
+      defaultLocale: 'default-locale',
+      queryParameter: 'lang',
+      cookie: 'languageCookie',
+      directory: './locales',
+      preserveLegacyCase: false
+    });
+  });
+
+
+  describe('should result in the same locale whether set by cookie, queryParam, or header', function () {
+    it('should work for simple language codes', function (done) {
+      (setByQueryParam(i18n, 'en')).should.be.equal('en', 'when set via queryParameter');
+      (setByCookie(i18n, 'en')).should.be.equal('en', 'when set via cookie');
+      (setByHeader(i18n, 'en')).should.be.equal('en', 'when set via header');
+      done();
+    });
+
+    it('should work for compound language codes', function (done) {
+      (setByQueryParam(i18n, 'de-AT')).should.be.equal('de-AT', 'when set via queryParameter');
+      (setByCookie(i18n, 'de-AT')).should.be.equal('de-AT', 'when set via cookie');
+      (setByHeader(i18n, 'de-AT')).should.be.equal('de-AT', 'when set via header');
+      done();
+    });
+  });
+});