subject matter

1. N-UNCOUNT The subject matter of something such as a book, lecture, movie, or painting is the thing that is being written about, discussed, or shown. (著作、讲话、电影或绘画的) 主题

Then, attitudes changed and artists were given greater freedom in their choice of subject matter. 然后，态度转变了，艺术家们在主题的选择上被给予了更大的自由。