Year 556 (DLVI) was a leap year starting on Saturday of the Julian calendar. The denomination 556 for this year has been used since the early medieval period, when the Anno Domini calendar era became the prevalent method in Europe for naming years.

• King Chlothar I suppresses a revolt of the Saxons and Thuringii in Saxony (Germany). For some time he exacts a tribute of 500 cows every year.

• King Cynric and his son Ceawlin of Wessex fight against the Britons at Beranburh, now identified as Barbury Castle (Wiltshire) in South West England.^[1]

• Lazic War: A Byzantine expeditionary force under Justin retakes Archaeopolis (modern Georgia), and routs the Persian army.^[2]
• Siege of Phasis: The Persians are defeated at the besieged town of Phasis in Lazica, held by the Byzantines.^[3]
• King Khosrau I opens negotiations with Justinian I, leading to the establishment of a 50 year peace agreement in 562.

• April 16 – The diplomatic representative (apocrisiarius) to Constantinople is elected as Pope Pelagius I, succeeding Vigilius as the 60th pope of Rome.

• Gao Bainian, crown prince of Northern Qi (d. 564)
• Amr Ibn Hashim, Arab pagan chieftain, and biggest enemy to the spread of early Islam

• February 22 – Maximianus, Bishop of Ravenna (b. 499)
• Echu Tirmcharna, king of Connacht (Ireland)
• Erzhu Ying'e, empress of Northern Wei
• Romanos the Melodist, Syrian poet (approximate date)
• Xiao Yuanming, emperor of the Liang Dynasty
• Yuwen Tai, general of Western Wei (b. 507)

• Bury, John Bagnell (1958). History of the Later Roman Empire: From the Death of Theodosius I to the Death of Justinian, Volume 2. Mineola, New York: Dover Publications, Inc. ISBN 0-486-20399-9.
• Greatrex, Geoffrey; Lieu, Samuel N. C. (2002). The Roman Eastern Frontier and the Persian Wars (Part II, 363–630 AD). London, United Kingdom: Routledge. ISBN 0-415-14687-9.
• Martindale, John Robert; Jones, Arnold Hugh Martin; Morris, J., eds. (1992). The Prosopography of the Later Roman Empire, Volume III: A.D. 527–641. Cambridge, United Kingdom: Cambridge University Press. ISBN 978-0-521-20160-5.