BlackBerry on Tuesday filed a patent infringement lawsuit against Facebook and two of its biggest subsidiaries, Instagram and WhatsApp. The suit, first shared by Reuters, claims Facebook developed competing applications that improperly use BlackBerry’s mobile messaging patents.

BlackBerry spokesperson Sarah McKinney told Reuters they have a strong claim that Facebook has infringed on their intellectual property and after years of dialogue, they also have an obligation to shareholders to pursue appropriate legal remedies.

Facebook is by far the world’s largest social network with more than two billion monthly active users. WhatsApp isn’t too far behind with an estimated 1.5 billion monthly active users and Instagram enjoys north of 800 million monthly actives. Facebook purchased Instagram for $1 billion in April 2012 before scooping up WhatsApp for $19 billion less than two years later.

BlackBerry was once a leader in the mobile phone industry but got a bit too comfortable with its position atop the perch. As companies like Apple, Google and Samsung set the modern smartphone revolution in motion, BlackBerry sat by idly – a move that ultimately proved to be its downfall.

Complicating matters was BlackBerry Messenger (BBM), a proprietary mobile messaging app launched in 2006 that effectively served as an alternative to traditional SMS / MMS messaging channels. This was important as the wireless industry at the time was transitioning from metered voice minutes to a finite number of texts each month. BBM played a huge role in all of this and eventually helped push the conversation to the data allotments that govern today's mobile usage.

BBM eventually came to Android and iOS in the summer of 2013 but by that time, standalone chat apps were already exploding in popularity.