Tiberius / Pax Group 2

Tiberius Group 2 Denarius, c. 15 - 18 A.D. Lugdunum mint.
O: TI CAESAR DIVI AVG F AVGVSTVS; One of the ribbons of Tiberius' laurel wreath falls over his neck.
R: PONTIF MAXIM; Triple line under throne, two above the exergue line (sometimes represented by a single base), Pax usually holds a reversed spear (as is the case in this example) instead of a scepter, the legs of the throne are ornately decorated, no footstool.

Baptiste Giard divides Tiberius' PONTIF MAXIM coins (aurei and denarii), into six groups, based on what he believes is the evolution of style over time. To some extent the portraits also reflect Tiberius' aging over a period of about 22 years. An excellent writeup can be found at http://www.forumancientcoins.com/numiswiki/view.asp?key=tribute%20penny.