I never said an army had been assembled, I said a small band of men had armed themselves. You said yourself that Catiline was surrounded by some 300 conspiritators, does 300 men qualify as an army ? I'm not so sure it does.
Maybe both of you would want to add a zero and some cohorts to that figure.
Here comes Sallust, "Bellum Catlina", Book LVI
"During these proceedings at Rome, Catiline, out of the entire force which he himself had brought with him, and that which Mallius had previously collected, formed two legions, filling up the cohorts as far as his number would allow;and afterward, as any volunteers, or recruits from his confederates, arrived in his camp, he distributed them equally throughout the cohorts, and thus filled up his legions, in a short time, with their regular number of men, though at first he had not more than two thousand."
Catiline might have been a scoundrel, but surely a popular scoundrel (especially if you considered all of this was after four eloquent Catilinarias and some nice executions).