When Was Rome Built??

Marilyn, the teacher, asked her 5th grade history class, "When was Rome built?" and called on Timothy to answer first. 

"Rome was built at night." was his answer. 

"At night?" asked Mrs. Taylor, holding her ruler firmly in her boney-knuckled hands. "How ever did you get such an idea?" 

"Well," gulped the student, hoping his answer would satisfy her, "everyone knows Rome wasn't built in a day."