#1: Valentinian II, I believe, reverse type SALVS REIPVBLICAE, Victory dragging captive, chi-ro symbol to left, Constantinople mint.
this one is similar, only minted in Nicomedia.
#2: can't tell, sorry.
#3: I can read "TIVS" tot he right of the portrait - the only option therefore is Constantius II. Reverse type is a very corroded FEL TEMP REPARATIO soldier spearing horseman. Very similar to
this one, though it's too far gone to read the mintmark.
#4: the spiky hairpiece means that this is a "radiate", or base-silver antoninianus, and is older than the others posted - mid to late 200's AD, rather than the 300's. I can't identify it any better than that, sorry.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis