Year 429 (CDXXIX) was a common year starting on Tuesday of the Julian calendar. At the time, it was known as the Year of the Consulship of Florentius and Dionysius (or, less frequently, year 1182 Ab urbe condita). The denomination 429 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. However, you can call it the 429th year of the Common Era and the Anno Domini designation, the 429th year of the first millennium, the 29th year of the 5th century, and the 10th and last year of the 420s decade.

• Spring – The Vandals, led by Genseric ("Caesar King"), invade North Africa. They land with a force of 80,000 men including Alans, and Germanic tribesmen with their families from the Iberian Peninsula, across the narrow Strait of Gibraltar. The Vandal fleet raids the coasts of the Mediterranean Sea, and blockades the grain and oil supply to Italy.^{[citation needed]}
• Genseric seizes lands from the Berbers and destroys church buildings all over Mauretania. He goes on a rampage forcing Bonifacius, Roman governor, to retreat to the fortified coastal town of Hippo Regius (modern Annaba).^{[citation needed]}
• Bonifacius, weakened by the civil war against empress Galla Placidia, sues for peace and is elevated to the rank of supreme commander (magister militum) of Africa.^[1]
• Emperor Theodosius II starts to reform the Codex Theodosianus in Constantinople. He establishes a committee to codify all Roman laws. All funds raised by Jews to support schools have to be turned over to the state treasury.^{[citation needed]}
• The Temple of Goddess Athena on the Acropolis of Athens is sacked. Athenian Pagans are persecuted.^{[citation needed]}

• Pope Celestine I dispatches two bishops from Gaul, Germanus of Auxerre and Lupus of Troyes to Britain combat the Pelagian heresy.^[2][3]
• Hilary succeeds his kinsman Honoratus and becomes archbishop of Arles.^{[citation needed]}
• Domnus II, future patriarch of Antioch, is ordained as a deacon.^{[citation needed]}

https://www.britannica.com/biography/Saint-Germanus-of-Auxerre

• Liu Jun, prince of the Liu Song dynasty (d. 453)
• Zu Chongzhi, Chinese mathematician (d. 500)

• January 6 – Honoratus, archbishop of Arles
• Heremigarius, military leader of the Suebi