Proton Mass from Theory

The Standard Model of particle physics is supposed to describe the properties of the quarks and gluons which make up the proton and other particles. Yet until just now isn't hasn't even been possible to calculate the mass of the proton based on the Standard Model.
See
The Weight of the World Is Quantum Chromodynamics in Science.
Nuclear masses calculated from scratch in Nature.
Particle physics: Mass by numbers by Frank Wilczek in Nature.

A highly precise calculation of the masses of strongly interacting particles, based on fundamental theory, is testament to the age-old verity that physical reality embodies simple mathematical laws.