THE SUMMER OF BLOOD

[Victor]

After the death of Constantine on 22 May 337, there was an interregnum of some three months before his three sons were proclaimed Augusti on 9 Sept 337. It was during these three months that The Great Massacre occurred, when most of the other male members of Constantine's family and their supporters were killed. During this period all the mints continued producing the GLORIA EXERCITVS, but Rome, which was controlled by Constans, issued some new types. one of these was the SECVRITAS REI PVB. Constans wanted the citizens to believe that the security of the Empire had been protected by the massacre.

 
For more on this, see the article

 

Burgess, R.W. THE SUMMER OF BLOOD. The "Great Massacre" of 337 and the Promotion of the Sons of Constantine. Dumbarton Oaks Papers 62, 2008.



Constans
A.D. 337-340
15mm  1.5gm
DN FL CONSTANS AVG  laurel and rosette diadem, draped, cuirassed
bust right
SECVRITAS REI P  Securitas standing facing, legs crossed,
head turned right, holding sceptre in right hand, left
elbow leaning on column.
Exergue is unclear
Rome

[Victor]

Here are coins from two of Constantine's family killed in the purge-- the brothers Delmatius and Hannibalianus.

the first is -

Delmatius
A.D. 335-7
16mm  1.4gm
FL IVL DELMATIVS NOB C, laureate and cuirassed.bust
GLOR-IA EXERC-ITVS [The glory of the army] Two soldiers helmeted, stg. facing one another, reversed spear in outer hands, inner hands on shields resting on the ground; between them one standard.
In ex. SMKB
RIC VII Cyzicus 132

and the second-

Hannibalianus
A.D. 335-337
15mm   1.5gm
FL HANNIBALIANO REGI, draped and cuirassed bust r.
SECVRITAS PVBLICE, Euphrates seated r., leaning on sceptre with urn at his side and reed in background.
In ex. CONSS
RIC VII  Constantinople 147

[Victor]

There is another fairly recent article on this topic that differs a bit with the Burgess article. David Woods, in his article "Numismatic Evidence and the Succession to Constantine I," writes that maybe the purge was actually a result of the actions of the soldiers (as a primary source states) rather than something instigated by Constantius II. Maybe Delmatius was actually guilty of something and troops loyal to Constantine's sons dealt with the situation in typical Roman military fashion.

I have links to both articles on this page-

http://www.constantinethegreatcoins.com/articles/