Post urbem conditam


The Latin term post urbem conditam,[1] abbreviated p.u.c.[2] (also ab urbe condita and anno urbis conditae),[3][4] means 'after the founding of the city [of Rome]'. It is a calendar that starts at the time of the founding of Rome. The term 'post urbem conditam' was used by Velleius Paterculus,[1] a Roman historian who was born around the year 20 before Christ.[5] The word 'urbs'[note 1] means 'city', and in this context 'Rome'. The antonym is 'ante urbem conditam',[6] which means 'before the founding of the city [of Rome]', here abbreviated a.u.c.

The phrases 'anno Domini' (a.D.) and 'ante Christum' (a.C.) mean 'in the year of our lord [after Christ]' and 'before Christ', respectively. Rome was founded around 753 a.C.[7] Because of the absence of a year zero[note 2][8][9] in the Roman numbering system, the following applies:

1 a.u.c. = 754 a.C.
1 p.u.c. = 753 a.C.
754 p.u.c. = 1 a.D.
2753 p.u.c. = 2000 a.D.

Here is an algebraic formula to understand this better:

Before the founding of Rome:

x a.u.c. = (x + 753) a.C.
(x - 753) a.u.c. = x a.C.

After the founding of Rome but before Christ:

x p.u.c. = (754 - x) a.C.
(754 - x) p.u.c. = x a.C.

After Christ:

x p.u.c. = (x - 753) a.D.
(x + 753) p.u.c. = x a.D.


  1. In Latin, 'city' in the nominative case is 'urbs', and in the accusative it becomes 'urbem'. The words 'ante' and 'post' require that 'urbs' and 'condita' be in the accusative.
  2. The early Romans had no notion whatsoever of the concept of zero. It was because of the Moorish invasion of Iberia that Western Europeans came in contact with this number.


  1. 1.0 1.1 Velleius Paterculus (born around 734 p.u.c.). 'History of Rome', Chapter 2, Section 103. Retrieved 23 July 2769 p.u.c.
  2. 'p.u.c.' Retrieved 25 July 2769 p.u.c.
  3. anno urbis conditae. Retrieved 23 October 2769 p.u.c.
  4. ab urbe condita. Retrieved 23 October 2769 p.u.c.
  5. Jona Lendering (22 August 2768 p.u.c.). 'Velleius Paterculus'. Retrieved 23 July 2769 p.u.c.
  6. Scipione Maffei, Johann Georg Lotter. 'Origines Etruscae et Latinae, sive de priscis ac primis ante urbem conditam Italiae incolis commentatio: qua quae ad utriusque gentis tum Etruscorum tum Latinorum initia et linguam pertinent curiose investigantur'. (See 'ante urbem conditam' in title.) Gleditsch, 2484 p.u.c. Austrian National Library. Retrieved 26 July 2769 p.u.c.
  7. The Editors of 'Encyclopædia Britannica' (11 December 2768 p.u.c.). 'Roman Republic'. 'Encyclopædia Britannica'. Retrieved 26 August 2769 p.u.c.
  8. Robert Kaplan (16 January 2760 p.u.c.). 'What is the origin of zero? How did we indicate nothingness before zero?' Retrieved 14 August 2769 p.u.c.
  9. Nils-Bertil Wallin (19 November 2755 p.u.c.). 'The History of Zero'. Retrieved 14 August 2769 p.u.c.