I'm trying to find the title of a book a read when I was young. I read it in the early 2000s, but it was definitely not a new book at that point. The plot focused on two kids (boys I think) who somehow travelled back in time to see important places/events/people in history. The only part I can remember clearly is that they met Archimedes and saw him get killed by Roman soldiers during the siege of Syracuse right before travelling somewhere else. I also have a vague memory that they used a magic book as their time machine, but this could be completely wrong.
Katherine, Andy, and Zach must stitch Time when they see a Time Wave while waiting on the school bus. When they try to warn Archimedes of danger, they must evade the soldiers who are determined to stop them.
Possibly not matching, the earliest copy I've found is from 2011, although all three books were listed as a Kindle publication in that year, so they may be a new publication of an older book now out of print.