Ajax doesn't work after using _remap

If I doesn't use _remap then I need to make url like this mywebsite.com/history/index/12 because it is saying that "page is not found", is there a way to remove that "index" from url somehow ?

Also with those you suggested I am getting errors when page is loaded
Message: Undefined property: History::$request
Message: Trying to get property 'uri' of non-object
Message: Call to undefined method CI_URI::getSegments()

EDIT
I removed _remap and made route like this $route['history/(:any)'] = 'history/index/$1'; this fixed all.