Magisterium is a blend of three distinct 16-year Single Blended Rums, distilled in the copper Double-Retort Pot Still and the Continuous Twin Column Coffey Still of Foursquare. Two of the rums were double maturations, one aging three years in ex-Bourbon casks, then 13 additional years in Ex-Oloroso Sherry Barrels; the other aging nine years in Ex-Bourbon followed by seven years in Ex-Oloroso Sherry. The last was a Single Blended Rum matured entirely in Ex-Bourbon Casks for 16 years. All blending, bottling, and aging occurred entirely on-site by Master Distiller and Master Blender Richard Seale of Foursquare Rum Distillery in Barbados.