The μ Herculis system solved after nearly three centuries

μ Herculis is a bright, nearby quadruple system. Its brightest member, μ Her Aa, displays solar-like oscillations, establishing the system as a crucial benchmark for asteroseismology, provided that its mass can be determined independently of stellar models. We aim to resolve the full hierarchical architecture of the system and determine precise, model-independent dynamical masses for all four components (Aa, Ab, B, and C), along with a consistent astrometric solution for the system's centre of mass. We performed a joint fit of radial velocities, relative astrometry and absolute astrometry from, DR3, and ground-based catalogues, spanning nearly three centuries. Our forward-modelling framework simultaneously constrains the Keplerian orbits of the inner Aa–Ab and B–C subsystems, the wide A--BC orbit, and the sky motion and parallax of the total centre of mass. Hipparcos Gaia Leveraging several complementary datasets and the decisive 2023 periastron passage of the Aa–Ab pair, we precisely determine all orbital parameters and obtain sub-percent precision on the component masses: M_ ̊m Aa = 1. 134± 0. 007, M_⊙, ̊m Ab =0. 2286 ± 0. 0006, M_⊙, M_ ̊m C = 0. 445 ± 0. 005, M_⊙, and M_ ̊m B = 0. 417 ± 0. 005, M_⊙. We derive a system parallax of ϖ_ ̊m CM = 120. 069 ± 0. 089, that reconciles and improves upon the individual and DR3 values. mas Hipparcos Gaia