 The Sundial Room , also called the Meridian Hall , was once the residence of Queen Christina of Sweden , then newly converted to Catholicism . The room was further modified by two additions which gave it its current name : a sundial , and a delicate but sophisticated anemoscope which was fixed to the ceiling of the Meridian Hall . These were created by Ignazio Danti , the papal cosmographer , in association with the Gregorian Calendar Reform . The sundial consisted of a straight line in white marble running across the floor in a north @-@ south direction , intended to measure the height of the Sun at noon according to the seasons of the year . The observations made with the sundial provided essential confirmation of the need to reform the Julian calendar . The anemoscope , in contrast , was a complex mechanism attached to the ceiling which was used to measure the strength and direction of the wind but soon stopped functioning . The instrument may have led to the other name of the tower , Tower of the Winds ; however , an ancient observatory at Athens was also called the Tower of the Winds and might have been the source for inspiration . 
 The Sundial Room , also called the Meridian Hall , was once the residence of Queen Christina of Sweden , then newly converted to Catholicism . The room was further modified by two additions which gave it its current name : a sundial , and a delicate but sophisticated anemoscope which was fixed to the ceiling of the Meridian Hall . These <a href='uninflect' title='1'><mark>were</mark></a> created by Ignazio Danti , the papal cosmographer , in association with the Gregorian Calendar Reform . The sundial consisted of a straight line in white marble running across the floor in a north @-@ south direction , intended to measure the height of the Sun at noon according to the seasons of the year . The observations made with the sundial provided essential confirmation of the need to reform the Julian calendar . The anemoscope , in contrast , was a complex mechanism attached to the ceiling which was used to measure the strength and direction of the wind but soon stopped functioning . The instrument may <a href='been_done' title='2'><mark>have</mark></a> led to the other name of the tower , Tower of the Winds ; however , an ancient observatory at Athens was also called the Tower of the Winds and might have been the source for inspiration . 
The Sundial Room , also called da Meridian Hall , was once tdaresidence of Queen Christina of Sweden , then newly converted to Catholicism . The room was further modified by two additions which gave it its current name : a sundial , and a delicate but sophisticated anemoscope which was fixed to the ceiling of thdaeridian Hall . dem was created by Ignazio Danti , thedapal cosmographer , in association wit the dagorian Calendar Reform . The sdaial consisted of a straight line in white marble runnin across the floor in a north @-@ south direction , intended to measure the hedat of the Sunda noon according to the seasons of the year . The observations made with the sundial provided essential confirmation of the gotta reform the Julian calendar . The anemdaope , in contrast , was a complex mechanism attached to the ceiling which was used to measure the strength and direction of the wind but soon stopped functioning . The instrdant may done led to the other name of the tower , Tower of the Winds daowever , an ancient observatory at Athens was also called the Tower of the Winds and might have been the source for inspiration .