This paper deals with the identification of Portuguese pre-colonial and colonial diplomatic agents who initiated and effectively implementedthe mechanisms and tools of 3Es for 400 years in Angola from 1575 to 1975. The study briefly presented two main actors countries of Central Africa and Western Europe, Monarchical figuresand Republican Presidents as holders of appointed diplomatic field agents in their different ranks and portfolios. The scrutiny of specialized sources, related scientific materials, different types of reports pertaining to these Portuguese agents in Angola and other institutional documents facilitate us to use a historical analytical approach with evidences drawn from variety of sources. The interpretation of evidence and findings shows that African history is frequently studied with some negligence with much lacking to disclose those European agents who strongly defended their countries by cheating Africans human and natural resources.The awareness of the above can likely opens new research avenues in the 21st Century. Our findings shows that within the period of the study, there were a total of 158 Portuguese official agents with 102 pre-colonial agents between 1575 and 1885 and 56 colonial agents from 1886 to 1975.Finally, about 23 elected or appointed Portuguese saved as President and Head of State during the colonial era spanning from 1910 to 1975.Comparatively to negligence of other European exploiters, the Portuguese at least tried to develop Angola. Therefore, this study is limited to the above as a means of building a historiography of 3Es agents which are often lacking in history books.