<P> The Gregorian calendar is internationally the most widely used civil calendar . It is named after Pope Gregory XIII , who introduced it in October 1582 . </P>
<P> The Gregorian calendar is internationally the most widely used civil calendar . It is named after Pope Gregory XIII , who introduced it in October 1582 . </P>
why is our calendar called the gregorian calendar
why is our calendar called the gregorian calendar
named after Pope Gregory XIII
named after Pope Gregory XIII