In what century did the Latin alphabet replace the runic system in Old English writing?
Old English is one of the West Germanic languages, and its closest relatives are Old Frisian and Old Saxon. Like other old Germanic languages, it is very different from Modern English and difficult for Modern English speakers to understand without study. Old English grammar is quite similar to that of modern German: nouns, adjectives, pronouns, and verbs have many inflectional endings and forms, and word order is much freer. The oldest Old English inscriptions were written using a runic system, but from about the 9th century this was replaced by a version of the Latin alphabet.
With the division of the Roman Empire, the Western Roman Empire lost contact with much of its past. In the Middle East, Greek philosophy was able to find some support under the newly created Arab Empire. With the spread of Islam in the 7th and 8th centuries, a period of Muslim scholarship, known as the Islamic Golden Age, lasted until the 13th century. This scholarship was aided by several factors. The use of a single language, Arabic, allowed communication without need of a translator. Access to Greek texts from the Byzantine Empire, along with Indian sources of learning, provided Muslim scholars a knowledge base to build upon.