The Mater Amabilis™ beta high school plans (which can be found in the Mater Amabilis™ for High School Facebook group) recommend Europe: A History by Norman Davies for the European History textbook. The book has twelve parts, which divides nicely into three parts each for four years. (Or, for those who want to finish in a shorter time, four parts each for three years.)
This is a dense and meaty text. It begins with a description of Europe's geography and a discussion on how its geographical features lend themselves to the development of a civilization. Part II covers Ancient Greece and Part III is Ancient Rome. These are the three parts we read in ninth grade (Level 5 Year 1).
I have recently prepared a study guide and mapping activities for the second three parts through the Middle Ages and up to 1493 (The Birth of Europe, The Middle Age, and Christendom in Crisis) for Level 5 Year 2.
Sally Thomas, one of the developers of the beta high school plans and a moderator in the Mater Amabilis™ Facebook groups began a study guide to provide definitions and guided questions. I started with her wonderful work and added mapping activities and finished it through Part VI. I will post those in the Facebook group.
The mapping activities ask my student to label a blank map with locations mentioned in the text. Personally I find that kind of preparatory work invaluable as I read a text because I am able to place events within a geographical space. My daughter has been doing these kinds of activities as she reads A Book of Discovery and has mentioned how beneficial she finds them as well.
I originally wrote the ninth grade study guide asking my son only to find the locations in our atlas, but I found throughout the year that he still couldn't remember even the most common locations from the text. So I wrote the tenth grade study guide to be more active as he labels a blank map, using our atlas to guide him. (I also went back and quickly revised the ninth grade one so it's ready for First Daughter.) I'm hopeful this additional engagement will help him form an internal map of Europe he'll be able to use throughout his life.
I have the third edition of the National Geographic Concise Atlas of the World which I have found sufficient though its more manageable size is possible by including fewer features and locations. There were a couple of things I just added myself (Nicaea, Mt. Athos, and Corinth, for example).
There are some maps within the text, but most tables and maps are relegated to the Appendix and most of those present multiple layers of information in a single page. My current high school student is the kind to immediately dismiss any thought of turning to the back of the book for additional information, so if I wanted him to look at something in the Appendix, I specifically required it in the study guide I wrote. I also supplemented the text with just a few maps in the study guide.
Because this text is so very dense, in the first year I often assigned only three or four pages. In the second year, I've increased that to an average of five pages. I think this will be acceptable as even my son agreed Davies was easier to digest after some practice. I also think the first chapter was the most difficult; it was much more abstract than the later ones. Part IV on the Birth of Europe is also more abstract than the following two parts.
While this book is used as a text in some college courses, it is an unusual choice for high school, partly because of its difficulty but also it's not a "textbook." Davies presents his own views alongside what others have said but without always identifying the "right" theory. Because it has only one author, it is easy to begin discussions by asking whether Davies is right: Does he present persuasive arguments? Have you learned something from another course or author that counters what he is saying?
Davies comments on everything. By the end of the book, a student will have encountered innumerable ideas and interrelationships between them. I know some other families in the Facebook group have opted for other history curricula, but I think this is a solid choice and I'm pleased with it.
If you have multiple students who will be using this text, I recommend a hardcover version. It's a large book and I think the hardcover will handle multiple years of use by multiple children better than paperback. It's relatively inexpensive used. (I accidentally ended up with two copies so if you're local and want one, let me know.)
I have receiving nothing in exchange for this post. I purchased this book used (and discovered Kansas Dad had purchased it new decades ago). All opinions are my own. Links above to Amazon are affiliate links.