Due to Justin I's failing health (he had cancer), he needed to chose a successor.  His nephew, Justinian I, who was currently serving as an adviser was made co-emperor.  This coinage was a successful attempt to show through the coinage the succession order of Justin I to Justinian I.  It is thought that the last coinage type (with "lyre" backed thrones) were actually produced upon Justin I's death.  There are some subtle differences in the obverse legend that indicate such an event.

These coins have always had a special appeal and now this is the most complete collection that has ever been put together.  The closest collection (public or private) is Dumbarton Oaks with 7 specimens (6 different varieties).  Of the possible 19 varieties, this collection has 14.  And of the 11 major types, this collection has 10!

Currently (11/00), I am finishing a die study based on Dr. William E. Metcalf's 1987 work, "Joint Reign Gold of Justin I and Justinian I", published by the ANS in Numismatic Studies #17.  In my die study, there has been an exhaustive reexamination of the dies and I have tried to get a census of all known specimens.  The intention is to have it published mid-2001.

During the process of researching this coinage, the coin that Sear had listed as 115a is die linked to two other coins that definitely has an exergual line on the obverse.  The Tolstoi/Hermitage specimen that Sear cites is just a very late die state.