KP423 was selected from Kent, a Bourbon-related population from in southwestern India. Kent was introduced to Tanzania and elsewhere in East Africa in the 1920s as part of an intensive selection program at the Lyamungu Research Station in Tanzania, focused on quality and production. KP423 was released in Tanzania in the 1940s, and made its way to Uganda, where it is an important variety in Arabica-growing regions.
It is believed that Kent descends from the first Bourbon seeds brought out of Yemen to India by Baba Budan in 1670. The various Kent-derived varieties originate with a selection made by Mr. L.P. Kent in 1911 from a single tree growing in his Doddengooda Estate in Mysore, southwestern India. It has been widely planted in India since the 1930s. It is known as the first coffee selected for rust resistance, though that resistance has since broken down.