A bit tricky from the photograph in your link as it’s not all that clear. However, as a starting point, from the lighting and mood, and what I can determine from the subject matter it is reminiscent of the British Victorian neo-classical movement (Leighton, Alma-Tadema, Watts, et al.). Will have a dig around and come back if anything similar turns up.
Yeah, some late 19th-C. pre-Raphaelite business-- not my bag. Medieval topic would be typical of that movement. If it’s a lithograph from that period it could be worth that much, depending on the market-- if it’s a later reprint, who knows? Is this of personal interest to you?
I’m amused by the phrase “writing that could be Latin or French that reads “Cy Yert U Sieges””-- wha? Could be Latin or French writing? What does that mean? I’d like to see a better photo of that writing.