Oh wow. I have seen nice coins in museums etc. but to have them on my desk.... I have said for many years that I am in the wrong job....
Heritage had these (and a few others) raw at the Chicago show - gorgeous coins! Hopefully the estimates will be reasonable as the consignor paid a significant premium for them when they last sold.
Oh, that Matidia steals my heart. The coin show sound that makes you freeze, "Ding -- roll -- spin to flat on the floor."
The first thing that crossed my mind is where they came from as a group. With the date spread it would seem unlikely they were new finds. I know there are hundreds of old collection groups of all levels that enter/reenter the market all the time so it should be no surprise that an ocassional one is 'special'. It is sad that the nature of the hobby discourages provenances.
They are all out of previous sales. The Diadumenian is Ex Price, Hunt, Leu, Platt-Hall, Arthur Evans, Karnak Hoard. The Macrinus is ex Metropolitan Museum of Art, ex BMC (71). All can be found on Coin Archives. There were more coins in the collection of similar quality, they were on my desk 2 days ago and I didn't take the time to photo them. No loss of provenances.