“Rome wasn’t built in a day” is an old saying that means that great things take time. “I wasn’t on that job” is a second jocular line that is often added by managers and foremen. This joke is frequently credited to English football manager Brian Clough (1935-2004).
 
“Foreman Builder—No, p’r'aps not; but I wasn’t foreman o’ that job” was cited in Punch in 1913. The joke has had many slight variations over the years.
 
   
Wikipedia: Rome wasn’t built in a day
“Rome wasn’t built in a day” is an adage attesting to the need for time to create great things. It is the usual English translation of a medieval French phrase, “Rome ne fu[t] pas faite toute en un jour,” from the collection Li Proverbe au Vilain (published around 1190; reprinted here). The modern French form is “Rome ne s’est pas faite en un jour.”
 
The expression (as “Rome was not built in one day”) is given in English in John Heywood’s A Dialogue Conteinyng the Nomber in Effect of all the Prouerbes in the Englishe Tongue (c. 1538; reprinted here), while Queen Elizabeth referred to the idea in Latin in an address at Cambridge in 1563.
   
Chronicling America
13 February 1913, San Francisco (CA) Call, pg. 20, col. 3:
THE BUILDING OF ROME.
Foreman Builder—Now, then, you: hurry up, can’t yer!
Laborer—Orl right, boss; Rome wasn’t built in a day.
Foreman Builder—No, p’r'aps not; but I wasn’t foreman o’ that job.—Punch.
 
Google Books
18 June 1914, Life magazine, pg. 1120, col. 3:
Wasn’t a Foreman at Rome.
The new foreman was a hustler. Nothing escaped is eagle eye, and whenever he saw a workman suffering from a tired feeling he quickly woke him up.
 
So when he discovered a bricklayer snatching a quiet pipe behind a wheelbarrow his wrath arose mightily.
 
“What do you think you’re paid for? Get on with your job, if you don’t want to get fired pretty sharp.”
 
“All right, boss,” rejoined the workman. “Keep your ‘air on. Rome wasn’t built in a day, you know.”
 
“That may be,” rejoined the hustler, “but I wasn’t foreman of that job.”
—Kansas City Times.
 
Google Books
20 April 1918, The Judge magazine, pg. ?, col. 2:
The Reason Why
Sergeant—‘Ere! You ain’t getting along very fast with this job!
Tommy—Well, Rome wasn’t built in a day, you know.
Sergeant—I know all about that, my lad, but I wasn’t a Sergeant then.—Bystander (London).
 
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Real Leadership:
The 101 Collection
By John C. Maxwell
Nashville, TN: Nelson Business
2003
Pg. ?:
His men would tease him, “Scotty, don’t you know that Rome wasn’t built in a day?” “Yes,” he would answer, “I know that. But I wasn’t foreman on that job.”
 
Google Books
Father Myron, a Novel
By Rod Mills
Xlibris Corporation (Xlibris.com)
2011
Pg. 311:
The old adage ‘Rome wasn’t built in a day, but I wasn’t foreman on that crew’ is the perfect picture of Dr. Lugene Sanders, and I wouldn’t trade that marvelous woman of God for anything.
   
Google Books
The Mammoth Book of Irish Humour
By Aubrey Malone
London: Constable & Robinson Ltd.
2012
Pg. ?:
Rome wasn’t built in a day, but then I wasn’t on that job. Brian Behan
 
Twitter
BBC Inspire
‏@BBCInspire
The answer to today’s quote quiz who said “Rome wasn’t built in a day. But I wasn’t on that particular job?” The answer: Brian Clough
8:41 AM - 7 Jan 14 from Westminster, London