Why does type subclass object?

Question

I am learning the Python data model. I have read this article.

In this question @poke answered how the built-in function isinstance works. It explained:

>>> isinstance(type, object) #Because type.__base__==object
True
>>> isinstance(object, object)
True

So my question is why type.__base__==object? and issubclass(object,object)==True when object.__bases__==() ?

Is it just for keeping unification of "everything is a instance of object"?