 and a succession of writings of the classical era all bore evidence of
  Ethiopia’s political and commercial notoriety.

Source: Adejumobi
Even before then, Pope Eugene IV had invited Ethiopian copts to the Council of Florence in 1439, the Africans arriving in 1441. The Ethiopian emperor also initiated contact (acknowledgement: Peter Taylor) by sending a diplomatic mission to Alfonso V of Aragon:

A Spanish king wrote to Emperor Zara Yakob (1434–68), described as a
  fanatical Christian who not only encouraged the writing of books, the
  building of churches, and the instruction of the public through
  teaching but also helped established religious nationalism and
  Ethiopian identity.

Source: Adejumobi
There were many contacts with the Portuguese and Jesuits in the 16th and 17th centuries, though attempts to impose papal supremacydid not go down well. Despite these, and subsequent, doctrinal differences, the European perception of Ethiopia was notably different to that of other regions of Africa. In the mid 19th century and the early 20th century, this was exploited by Tewedos and his successors through the Ethiopian churches; previous contacts gave Ethiopian rulers the kind of access to European governments which other African leaders either didn't have or were unable to use to their advantage.
Referring to both Ethiopia and Liberia, M. B. Akpan in Liberta and Ethiopia, 1880-1914: the survival of two African states writes:

both were able to play one European power against the other and were
  able to resist by diplomacy the more indirect pressures of the
  colonial powers. Menelik certainly succeeded in playing Italy,