What is the primary purpose of most constitution

Depends from government to government but a democracy normally has a constitution to ensure and protects citizen's rights.

For example:

The Constitution of the United States ensures in the first amendment that we have freedom of speech, to press, and to peaceably assemble while the second is the right to bear arms.

the crusades are one of the most significant events in the history of europe and the middle east.   they were a series of religious wars carried out by christian crusaders from europe during the timeframe of the middle ages.   beginning in 1095 ce, the crusades saw european knights and noblemen travel to the middle east in an attempt to capture the holy land away from muslim people that had controlled the region for the previous centuries.   the term crusade means ‘cross’.   therefore, the europeans that became crusaders viewed themselves as ‘taking up the cross’.   in fact, many of the crusaders wore crosses on their clothing and armor as they made their pilgrimage to the holy land.

explanation:

by 1880, germany had more rail lines than great britain and russia.