½ Real - Philip II

The early issues of Potosi, use the same monogram and crown (with small variations) until 1580, when Juan Alvarez Reinaltes ("A") took over the office of assayer. Under his tenure, the coinage was slightly redesigned, but the changes show most dramatically on the 1/2 real, see here https://www.acsearch.info/search.html?id=3115172 A new style of crown was first used in that year, along with a new version of the monogram, of the same design. His issues From 1580 onward, the crown is large, with large trefoils and has pellets in a rectangular brim. This is especially useful in identification of the later issues of B and those of Baltasar Ramos Leceta, who used only a small letter "R" on the half real, always to the left below the letter P - see here https://www.acsearch.info/search.html?id=2440104 This is important to note as his coinage is often confused for that of the first assayer, Rincon, who also used an R - but on coinage of the initial "Lima" design.