1274

1274 is a year in the 13th century and also a natural number with distinct mathematical properties. The number 1274 factors as 2 × 7^2 × 13. It is even and composite, and its proper divisors sum to 1120, making it a deficient number. The digit sum is 14, and 1274 is divisible by 14 (1274 ÷ 14 = 91), so it is a Harshad (Niven) number in base 10.

In historical terms, 1274 is best known for the Second Council of Lyon, convened by Pope Gregory X in Lyon, France. The council opened in 1274 and continued into 1275, with the goal of healing the East–West Schism between the Roman Catholic and Eastern Orthodox churches. It produced a provisional agreement for church reunion, commonly referred to as the Union of Lyon, which endorsed papal primacy and certain doctrinal formulations. The union was proclaimed in some circles as an accord between the Western and Eastern churches, but it did not achieve lasting acceptance within the Byzantine world and its terms did not endure, as relations between East and West remained divided in the following decades.

Beyond the council, 1274 fell within a period of ongoing dynastic, political, and religious activity characteristic of the medieval era. Regions across Europe and the broader Mediterranean world experienced the slow, incremental changes of feudal power, ecclesiastical influence, and inter-state diplomacy that defined the late Middle Ages. No single global milestone from 1274 stands alongside the council in historical prominence, but the year is often cited for its significant ecclesiastical diplomacy.