1265
1265 is the year of the first English parliament to include commoners.
- Odd
- Composite
Where 1265 fits
Why 1265 is special
Simon de Montfort summoned representatives from towns as well as nobles, while in rebellion against the king. Its origin as a rebel assembly is usually left out of accounts that trace parliamentary democracy to it.
Same number, different meanings
How 1265 is understood across different contexts — never implying one meaning because of another.
- Mathematics
Simon de Montfort summoned representatives from towns as well as nobles, while in rebellion against the king. Its origin as a rebel assembly is usually left out of accounts that trace parliamentary democracy to it.
- History
In 1265, Simon de Montfort summoned a parliament including elected burgesses, a step towards the House of Commons (England).
- Law & regulation
The 1265 parliament included burgesses from the towns for the first time and was called by Simon de Montfort while at war with Henry III. Its status as a foundation of representative government sits awkwardly with its origin as an insurgent measure.
1265 is part of
Factors & digit properties
- Divisors (8)
- 1, 5, 11, 23, 55, 115, 253, 1265
- Prime factorisation
- 5 × 11 × 23
- Digit sum
- 14
- Digital root
- 5
Representations
- Decimal
- 1265
- Scientific notation
- 1.265 × 10^3
Roman numerals
M C C L X V
Binary
1 0 0 1 1 1 1 0 0 0 1
1 × 1,024 + 0 × 512 + 0 × 256 + 1 × 128 + 1 × 64 + 1 × 32 + 1 × 16 + 0 × 8 + 0 × 4 + 0 × 2 + 1 × 1 = 1,265
Octal
2 3 6 1
2 × 512 + 3 × 64 + 6 × 8 + 1 × 1 = 1,265
Hexadecimal
4 f 1
4 × 256 + f × 16 + 1 × 1 = 1,265
Read as powers of two: 1,024 + 128 + 64 + 32 + 16 + 1 = 1,265.
In historical numeral systems
Egyptian
1 lotus, 2 coils of rope, 6 hobbles, 5 strokes
1 × 1,000 + 2 × 100 + 6 × 10 + 5 × 1 = 1,265. The signs are simply repeated and added; where they sit on the line is a matter of layout, not value.
Babylonian
2 corner wedges + 1 vertical wedge (sixties place), 5 vertical wedges (units place)
21 × 60 + 5 = 1265. Places are separated by a space on the tablet, with the higher place written first.
Systems that simply cannot reach this value are left out. Where a script needs a font most readers do not have, the reading is given instead of the glyphs — see number systems for each system in full.
Other mathematical patterns
- Deficient number
Related numbers & connections
1265 is a year in the 13th century, in the 1260s.
Numbers Around Us
- appears inHistorical years
why?
Strength 0.50, confidence "high".
History
In 1265, Simon de Montfort summoned a parliament including elected burgesses, a step towards the House of Commons (England).
DocumentedHistoryGeography: EnglandPeriod: 1265
Law & regulation
The 1265 parliament included burgesses from the towns for the first time and was called by Simon de Montfort while at war with Henry III. Its status as a foundation of representative government sits awkwardly with its origin as an insurgent measure.
DocumentedLaw & regulationGeography: EnglandPeriod: 1265
Common questions
Is 1265 a prime number?
No, 1265 is not prime.
What are the factors of 1265?
The factors of 1265 are 1, 5, 11, 23, 55, 115, 253, 1265.
What is 1265 in Roman numerals?
1265 in Roman numerals is MCCLXV.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 2 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 15 July 2026