Studying history especially ancient history will often require making decisions based on limited evidence why

In ancient history we can only study their cultures. This is because they didn't always have written records (or the records they did leave has been destroyed or damaged) hence no way to transmit their information. We have to guess on their everyday lives based on statues and art forms they left behind.

Muslim armies began attacking the Empire in 700, while Turk armies captured Constantinople in 1453.