In the widest sense, number theory is concerned with the properties of integers. This includes issues of partition into prime factors, divisibility, and the integer solutions of equations (“Diophantine equations”; see below, 1.3.). The early modern genesis of this discipline was heavily influenced by the reception of two ancient Greek works, the Elements of Euclid (c. 300 BCE) and the Arithmetica of Diophantus of Alexandria (3rd century CE) [1].