Explore ancient Greek number theory in this mathematics history lecture. Delve into the study of squares, triangular numbers, primes, and perfect numbers. Learn about Euclid's Fundamental Theorem of Arithmetic and its significance in factoring natural numbers into primes. Discover the Euclidean algorithm for finding greatest common divisors and its connection to continued fractions. Examine Pell's equation and its application in Archimedes' famous Cattle problem. Gain insights into the foundations of number theory and its historical development through this comprehensive exploration of Greek mathematical achievements.