Video: BMW looks back at the M535i - the M5's grandfather

YouTube / BMW

BMW has its fair share of performance 'M' cars on offer in 2015 – from the speedy but affordable M135i hatchback to the iconic M3 saloon and the heavyweight X5 M and X6 M performance off-roaders. These models are a far cry from the M division's roots, though, which started with the M1 supercar in the late 1970s.