in assembly

See: en masse
References in classic literature ?
In the meantime I will go to Ithaca, to put heart into Ulysses' son Telemachus; I will embolden him to call the Achaeans in assembly, and speak out to the suitors of his mother Penelope, who persist in eating up any number of his sheep and oxen; I will also conduct him to Sparta and to Pylos, to see if he can hear anything about the return of his dear father--for this will make people speak well of him.
Take my advice, call the Achaean heroes in assembly to-morrow morning--lay your case before them, and call heaven to bear you witness.