Saints Cyril and Methodius were two brothers from the Byzantine Empire who lived in the 9th century. They are best known for their missionary work in Great Moravia, where they sought to spread Christianity among the Slavic people. To help with this, they created the Glagolitic alphabet, which was the first alphabet used to write the Slavic languages, allowing the people to read the Bible in their own language. Their efforts laid the foundation for the development of Slavic literacy and culture. Today, they are celebrated as the patrons of Slavic peoples and are honored for their contributions to education and the spread of Christianity in Eastern Europe.