Throughout the 14th and 15th centuries, most European frames were church-commissioned and largely unmovable as they were altarpieces and a large part of the church’s architecture. The frames were ornamented with architectural elements mimicking the exteriors of the great cathedrals. However, the Renaissance of 14th and 15th century Italy saw the rise of arts patrons extending beyond the church. Wealthy nobles such as the Medici family could now bring art and frames into their estate by commissioning allegorical, devotional and portrait paintings.[11] This was the advent of the portable or moveable frame. – Wikipedia
