While the Eye of Providence is today a common Masonic motif, this was not the case during the 1770s and 1780s (the decades when the Great Seal was being designed and approved). According to David Barrett, a Masonic researcher, the Eye seems to have been used only sporadically by the Masons in those decades, and was not adopted as a common Masonic symbol until 1797, several years after the Great Seal of the United States had already been designed. The Eye of Providence was, on the other hand, a fairly common Christian motif throughout the Middle Ages and Renaissance, and was commonly used as such in Europe as well as America throughout the 18th century. It is still found in Catholic, Orthodox, and even some Protestant churches, and it symbolises the Holy Trinity (the triangle) and God's omniscience (the eye) surrounded by rays of glory, denoting God's divinity.