Maybe try /r/ArtHistory

So, Bosch was a Flemish painter during the Northern Renaissance. However, early Netherlandish art maintains it's own, independent characteristics and is considered more Late Gothic/Early Renaissance.

Around this time, The Netherlands, specifically Flanders, prospered through trade and craftsmanship, becoming very wealthy. As a result, religion played a more important role in society because they believed that earthly wealth could distract one from their relationship with God, thus their salvation. The art at this time aimed to depict scenes that were only ever before described in text.

Basically, Bosch was a very religious, moralistic man who warned of folly, sin and the temptations of earthly pleasures through his artworks, such as Garden of Earthly Delights. His inspiration comes from religious stories and from what he imagined them to look like. He's actually considered as the first surrealist painter.

There's so much more I could go into, but here's a [helpful link] (http://revolutionarypeoplefromtherenaissance.weebly.com/hieronymus-bosch.html) and an important quote, "He was alive when the towns were just coming out of the Dark Ages, so this influenced some of his paintings...He saw the little things in life, such as gargoyles and mini carvings, and decided to bring them to life in paintings...he let the horrors he saw everyday spill out onto his paintings, which was creative and different for his time period."

I hope I cleared some stuff up for you!