How to use forward declarations for a template class in a shared pointer (in C++)

I have a base class Base defined in Base.h:

class Base
{ /* ... */ };

And a class template Child that derives from Base, defined in Child.h:

#include "Base.h"

template <class T>
class Child : public Base
{ /* ... */ };

Now I want to create some factory methods within the Base class, which should return a std::shared_ptr to the Child class. To avoid circular dependencies I tried to use a forward declaration instead. So Base.h now looks like this:

class Child; // new forward declaration

class Base
{
    /* ... */

    // new factory method
    static std::shared_ptr<Base> CreateChildInt(int i = 0)
    {
        return std::make_shared<Child<int>>(i);
    }
};

However, the definition of CreateChildInt() leads to the following compiler error:

"error C2947: expecting '>' to terminate template-argument-list, found '<'"

So is this even possible what I am trying to achieve?
If not, are there any workarounds / best practices for this approach?

EDIT: The reason for why I want to put the factory method into the Base class instead of Child is the following. When I put the factory into Child I would need to call the factory method like this:

std::shared_ptr<Base> p = Child<int>::CreateChildInt(3);

However, I would like to omit the template type <int> in this call, thus:

std::shared_ptr<Base> p = Base::CreateChildInt(3);