There once was a curious custom in Athens called "ostracism". Ostracism was a process where. once a year, one citizen could then be exiled for a period a 10 years without loosing his citizenship of property - it was a safety measure against power hungry and ambitious politicians. The name derives from Ostrakon which means shard of pottery since this was the material that you wrote a name on.
All these pieces of ostraka spells one single name: Themistocles - a leading Athenian exiled in 472 or 471.