Like an unhappy marriage, Google this week divorced Motorola Mobility. The whole sordid tale reads like some sort of medieval bride-swapping ceremony designed to keep the peace between nations. And before anyone starts talking about how Google lost a lot of money overall on this deal, let’s keep our minds firmly focused on the singular reason Google bought Motorola in the first place: patents.

Motorola was in deep trouble in 2009, with billions in losses over the previous years. By 2011 it was two entirely separate companies: Motorola Solutions and Motorola Mobility. The latter was quickly courted by Google, but not for acquisition. Initially, Google just wanted the patent portfolio Motorola owned.

Even today, the cellphone industry as we know it is only about 20 years old. Anything that existed before 1994 or so bears no resemblance to what exists today in cellular phone services, technology and sales. And yet, Motorola has been in the cellphone business for well over 20 years.