This year, Revolution turns 20. Two decades of chronicling watches, people and ideas have given us a front-row seat to a remarkable story: how an age-old craft has both preserved its soul and reinvented itself for the 21st century. To celebrate, we’ve chosen over 100 names and milestones that, for us, define the era so far. From leaders to watches, you can see the whole list here.

MB&F’s Legacy Machine Perpetual rewrote the rules for one of watchmaking’s most traditional complications when it was introduced in 2015. Launched as part of Maximilian Büsser’s playful-yet-precise Legacy Machine series, the LM Perpetual didn’t try to out-ornament its peers or cram more subdials into a pageant of indications. Instead, it addressed the perpetual calendar’s perennial weaknesses at the mechanical level and did so with theatrical clarity: a massive, suspended balance on the dial, a clean, three-dimensional display, and beneath it, a fundamentally new way of thinking about the calendar itself.

MB&F Legacy Machine Perpetual

Now in this gathering of Revolution’s Top 100, we’ve also listed another innovation of the perpetual calendar in the 21st century, namely H. Moser & Cie’s. Call it a coincidence but it seems that the age-old complication has been radically reimagined by two independents. Where Moser’s Endeavour Perpetual Calendar was an exercise in restraint, MB&F’s solution was to redesign the calendar from first principles: instead of a conventional module, the LM Perpetual uses what MB&F describes as a “mechanical processor” that intelligently calculates month lengths and routes the complexity under the movement rather than across the dial.

That “mechanical processor” isn’t marketing fluff. Stephen McDonnell’s architecture starts from a default 28-day month and adds the required extra days for 30- and 31-day months through a carefully orchestrated set of mechanical logic gates. Crucially, the system includes safety measures that prevent the fragile calendar mechanics from being damaged by incorrect fast adjustments. The movement is fully integrated rather than module based, making servicing more straightforward and reducing cumulative tolerances that can bedevil conventional multi-layered QPs.

The fully integrated perpetual calendar caliber developed for MB&F by Stephen McDonnell

Aesthetically, MB&F kept the Legacy Machine promise: the dial is a stage. The oversized, suspended balance wheel sits proudly above the calendar display, which presents itself as a clean presentation — the exposé of the mechanical architecture is meant to invite admiration, not overwhelm — making the LM Perpetual surprisingly approachable for a grande complication.

The LM Perpetual insists on a different metric, and in doing so, it has become one of contemporary watchmaking’s most persuasive statements of modern know-how.

The oversized, suspended balance wheel sits proudly above the calendar display

Tech Specs: MB&F LM Perpetual

Movement: Manual winding, fully integrated perpetual calendar caliber, developed for MB&F by Stephen McDonnell; 72-hour power reserve
Functions: Hours and minutes; perpetual calendar with retrograde date and leap year
Case: 44mm × 17.5mm; 18K red gold, white gold or yellow gold, platinum, Grade 5 titanium, palladium or stainless steel; water resistant to 30m
Dial: Skeletonized with blue- or gray-treated bridges
Strap: Hand-stitched alligator leather with folding clasp