<P> At 5 : 15 a.m. , Richardson 's brigade fired a few artillery rounds across Mitchell 's Ford on the Confederate right , some of which hit Beauregard 's headquarters in the Wilmer McLean house as he was eating breakfast , alerting him to the fact that his offensive battle plan had been preempted . Nevertheless , he ordered demonstration attacks north toward the Union left at Centreville . Bungled orders and poor communications prevented their execution . Although he intended for Brig. Gen. Richard S. Ewell to lead the attack , Ewell , at Union Mills Ford , was simply ordered to `` hold ... in readiness to advance at a moment 's notice '' . Brig. Gen. D.R. Jones was supposed to attack in support of Ewell , but found himself moving forward alone . Holmes was also supposed to support , but received no orders at all . </P>
when did the battle of bull run start
5 : 15 a.m.