The Travels and Adventures of Edward Brown, published in 1739, describes impressions of the Jews of Abyssinia.
As for the Jews I am at a Loss what to say of them; for if we consider the several sorts of them who live in and round Abyssinia, and the Custom of the Abyssines themselves, to observe the Sabbath strictly, to circumcise on the eighth Day, to use the Levitical Purifications, to abstain from forbidden Meats, to send away their Wives on every slight Occasion with a Bill of Divorce, and to boast as they do that their Monarch is the Lion of the Tribe of Judab; I say when one considers all this, one might be tempted to say they are all Jews. But to avoid giving Offence, after seperating the Abyssines, who are a kind of Christian Jews, the remainder may be divided into Jews, properly so called, and into those who are Jews only by Descent. Of the first there are great Numbers in the Kingdom of Dambea; these were formerly very troublesome, pretending to live in an independent manner, without yielding either Tribute or Submission to the Abyssinian Emperors. These Princes for a Time wink'd at this, till an Opportunity serv'd for reducing them, against which, tho' to no Purpose, the Jews made a vigorous Resistance. Since then, many of them are turned Christians, and incorporated with the Abyssines, but the remainder of them now very numerous, are the most industrious Mechanics and Traders in the Abyssian Empire. On the very Borders of this Country, on the other Side of the Nile, and among the barbarous People, there are many independent Colonies of Jews, of whose Government and manner of living very little Account can be given, except that they have the Scriptures of the old Testament in Hebrew, speak themselves that Language corruptly, and most bitterly hate the Christians.This is an earlier account than the one mentioned in the Jewish Virtual Library that claimed that the first modern contact came in 1769.
As to those who are Jews only by Descent, they are the famous Nation of the Gaus, Gallas or Chalks, which last I take to be their true Name, at least so themselves pronounce it. It signifies white Men, and yet these People are black. However that they were once white is plain enough, for they have most of them them Roman Noses, thin Lips, and comely Features. They are tall, robust, well limb'd Men, very brave, but withal very cruel, and most abominable Thieves, It is not above an hundred Years that they have vexed the Abyssinian Empire, or indeed that they were ever heard of there; but in all probability it will be at least another hundred Years before the Abyssinian get fairly rid of them, for they are now settled up and down all the West Borders of the Empire. They live like the ancient Patriarchs, on the Product of their Herds and Flocks, never cultivating any Land, or Building any Thing more than Cabbins to cover them from the Weather. They worship one God, circumcise, and vehemently abhor Idolatry ; but as for any other religious Tenets, it does not appear what they hold. When their Children are young, their Fathers regard them no more than Dogs ; but when they are grown big enough to hunt, and to sight, then they treat them with all imaginable Kindness and Affection. These People are most justly accounted the most dangerous Enemies in the World; in offensive Wars they are generally Victorious, and when they act on the defensive are always so. When they sight they either conquer or die ; when they are attacked by a superior Force, they drive away their Cattel, and retire so quick, that their Pursuers are quickly involved in their inhospitable Country, where there is neither House, plow'd Field, or any Thing which can furnish Subsistance ; so that there is a Necessity of retiring Re infecta; and it is well if these People do not incommode their Retreat. Their Armies are composed of Horse and Foot, the former are the more numerous, but the latter arc the better Troops.