A Brief History of Quaternions and of the Theory of Holomorphic   Functions of Quaternionic Variables
  In this paper I will give a brief history of the discovery (Hamilton, 1843) of quaternions. I will address the issue of why a theory of triplets (the original goal of Hamilton) could not be developed. Finally, I will discuss briefly the history of various attempts to define holomorphic functions on quaternionic variables. 
Amy Buchmann
math.HO