What is the time singutaure?

The time signature (also known as meter signature, metre signature, or measure signature) is a notational convention used in Western musical notation to specify how many beats (pulses) are contained in each measure (bar), and which note value is equivalent to a beat.

giovanni battista pergolesi, italian baroque composer who wrote one of the most famous settings of the stabat mater. don lorenzo perosi, catholic priest and director of the sistine choir under five popes.