I am not a historian, but I am an archaeologist with an MA and PhD in Ethiopian historical archaeology. Ethiopian history can be a little fuzzy at times, and we have many blank spots up to the late 13th century. However, to our collective knowledge, I don't think we have any evidence that an Ethiopian king ever traveled to Jerusalem or other Mediterranean destinations (not saying they didn't travel elsewhere in the region of the Horn). Following the Aksumite period, Tamrat (1972, Church and State in Ethiopia) claims that the 11th century Zagwe King Yemrehana Krestos desired to travel to Jerusalem, but his advisers told him he was needed too much at home to make such a long journey away. In his stead, he sent a cadre of priests on his behalf, who each brought back symbols of their pilgrimage. It is these pilgrims who are supposedly interred behind the church of Yemrehana Krestos, though no one to date has scientifically validated this. HOWEVER, while doing some survey work in the Lasta region, I and the team I was working with, identified three identical processional crosses of Eastern Mediterranean design at three different Zagwe period churches, including Y.K., that could be contemporaneous. There are no records of any other Ethiopian monarch traveling far beyond Ethiopia's shifting borders before the modern period that I have heard of. Supposedly the Zagwe king Lalibela (r. 12th-13th century) built the 11 rock-hewn churches of the modern town of Lalibela as a "new Jerusalem" for pilgrims unable to make it to the Holy Land because of the Crusades . This seems more apocryphal than anything else, however, as there is fair evidence the churches were built over time, and not all as churches originally, and that many Holy Land toponyms used in the area today came about later.
The general course of post-Aksumite Ethiopian history seems to be that the Ethiopian kings were often too preoccupied with tumultuous affairs, secular and religious, within their own state to have the time or capacity to travel abroad. However, they often maintained numerous lines of contact with places further afield, through diplomatic missions, attachment to the Alexandrian Patriarchy, and contracted caravan merchants.
This is not to say, however, that other Ethiopians didn't range far abroad. When European crusaders reached Jerusalem, they encountered a group of Ethiopians among the contingents of churches represented at the Church of the Holy Sepulcher. The Catholic Church also supposedly hosted some Ethiopian monk-diplomats at a guest house for some time in the late Middle Ages, and the 17th-century German orientalist Hiob Ludolf wrote extensively about Ethiopia from accounts given him by an Ethiopian living in Europe. Europeans likewise traveled to Ethiopia regularly from the lat Middle Ages onward, most notably the 16th century Portuguese embassy narrated by Fransisco Alvares and the Jesuit missions to Ethiopia (1557-1632).
Edit: All this is not to say that there aren't anecdotal accounts of Ethiopian kings making pilgrimages to Jerusalem from external sources or non-contemporaneous (often centuries later) sources, but these are hard to verify and likely prone to exaggeration. Possibly some late Aksumite or Early Medieval kings did, when first-hand, contemporary sources are sparse, but there are no records to my knowledge of kings after 1270 traveling far beyond the borders of the state prior to the 20th century.
Hey all,
If you frequent the sub, you know the drill. If you're here from /r/all, or browse only occasionally, please be aware we have strict rules here intended to enforce the very high bar we expect from comments, so before posting, please read our rules. We remove comments which don't comply, and consider everyone forewarned. If you have feedback or commentary about how things are run here, please don't post it in this thread. We'll just remove it. We love to hear thoughtful, constructive feedback via modmail however.
It can take time for an answer to show up, so we thank you for your patience. If you want to be reminded to come check back later, or simply find other great content to read while you wait, this thread provides a guide to a number of ways to do so, including the RemindMeBot or our Twitter.
Again though, please remember the rules, and keep them in mind while you browse. If you don't like how this subreddit is run, keep in mind that this method has seen us continue to succeed and grow for years, and isn't going to change, so at least try and make your complaint original. /r/AskHistory exists, so complaining about the rules to us is like going into a fancy restaurant to complain they don't sell chicken nuggets, even though Chick-fil-A is nextdoor.
P.S. If you are thinking about posting "Look at Mansa Musa", please don't. He was a Muslim ruler from Mali, not a Christian King from Ethiopia. Almost every top level post removed is about him, but he is not the answer to this question (and even if it was the answer, they are all far too shallow to fit our rules anyways, but that is another matter).