Like many artists early in their careers, I was somewhat intimidated by the masters of the past, and in my case they were the Heidelberg School artists of the late 19th century. But never mind them, what about Rogier Van Der Weyden (about 1399-1464).
His "Descent From The Cross" (c.1435) measuring approximately 2.6 metres wide is considered one of the masterpieces of the Renaissance. It is a triumph of draftsmanship, composition and emotion. The clear, cool colours of the new oil paintings which were just appearing on the scene at this time are another highlight. I'm not of a religious inclination at all, but I do acknowledge the contribution religion has made to art and architecture.
If you care to look, you will find on Youtube a 5 minute segment from the series "The Renaissance Unchained" hosted by Waldemar Januszczak featuring this painting. It is a very moving account of a work of genius which was a commission from the Cross Bowman's Guild - hence the shape formed by Christ's body.