Classical languages
Latin was the language of ancient Rome (the Roman Empire), about the time of the birth of Jesus Christ. When used together like this, Greek means the language used in ancient Greece, at the time (before the birth of Jesus Christ) when it was the centre of European civilisation. These two languages (both now 'dead' languages - i.e. with no living speakers, ewxcept as second languages) are so important in the history of European scholarship that they are called the classics.
The importance is that they were the language of all education higher than Primary School, throughout Europe. This was particularly true of Latin, which was the language of instruction in universities from their beginning to after the Reformation of the church, in the 16th century. Greek was less known. Indeed, it was hardly studied in western Europe from the fall of Rome, as the centre of the Roman Empire, until the capture of Constantinople (now called Istanbul) by the Ottomans in 1453. After that, the importance of the ancient Greeks as the originators of a greta deal of modern European culture began to be recognised, and studied in great depth. This is why Latin anfd Greek are sometimes called the learned languages - they were the languages of learning, understood by all educated people.