Boetius's *Arithmetica* is one example, from around 500 AD.  See the [manuscript][1], the [text][2], or a [summary][3]. The book provided a Latin version of Nichomachus’s *Arithmetica* (which was in Greek from around 100 AD), which in turn covered some of the number-theoretic topics in Euclid’s *Elements* (from around 300 BC). All three books discussed the sieve of Eratosthenes, the Euclidean algorithm, and perfect numbers.


  [1]: http://www.maa.org/press/periodicals/convergence/mathematical-treasures-boethiuss-arithmetic
  [2]: https://archive.org/details/aniciimanliitor01friegoog
  [3]: https://www.jstor.org/stable/27957920