古英語, or Old English, is the earliest form of the English language, spoken and written in England from around the 5th to the 12th century. It evolved from the Germanic languages brought to Britain by the Anglo-Saxons, a group of tribes that included the Angles, Saxons, and Jutes. Old English is quite different from modern English, featuring a complex system of inflections and a vocabulary heavily influenced by Latin and Old Norse. The most famous work in Old English is the epic poem Beowulf, which reflects the culture and values of the time. Old English gradually transformed into Middle English after the Norman Conquest in 1066, leading to significant changes in grammar, vocabulary, and pronunciation. Today, Old English is primarily studied by linguists and historians to understand the development of the English language.