What do Pears have to do with Bradford Pear trees and why the name?

The Bradford Pear is a cultivated variety of the Callery Pear. Unlike most other pear trees this form is grown mainly for its ornamental features. The showy, white flowers appear during spring growth, often before the leaves. In contrast to their appearance, however, the flowers have an unpleasant odor. In autumn the leaves turn bright red to dark red before falling. The fruits are small and round, less than 1 inch in diameter, hardly resembling the traditional pear in appearance. While on a tree they are hardly visible, being hidden by leaves.
What do Pears have to do with Bradford Pear trees and why the name?
They are a pear tree. They are just a horticultural version of the species that does not produce any fruit.