The Hospitaller knights of St Lazarus originally observed the Rule of Saint Basil.
In the 12th century, they began to follow the Rule of Saint Augustine. A version of this rule, dating from the beginning of the 14th century and combining the religious, hospitaller and military life of the Order has been found in a very old Swiss commandery.
The year 1649 saw the printing of a Rule and Statutes which took into account the changes that the Order had undergone over the preceding two centuries and the annexation of the Order of Our Lady of Mount Carmel, with certain knights being allowed to marry, a less regulated life within the commandery, the practice of individual spirituality based on the daily reading of the Office of Our Lady. This Rule and these Statutes were to remain in force until 1830.
During the second half of the nineteenth century, the Knights of St Lazarus were governed by a Fundamental Statute adopted by the Council of Officers and the Patriarch-Protector.
In 1933, the rules and statutes were again redrafted to take account of modern realities, with the creation of the rank of Dame recalling the early Sisters of Saint Lazarus who cared for lepers and the status of Orthodox, Anglican and Protestant knights being officially regularised. As the pace of life increased in the succeeding decades, so the rule of life for members of the Order was revised and amended.
The Order of St Lazarus is now defined and governed by the Constitutional Charter adopted in Prague on 21 September 2006 and revised in Aigues Mortes on 10 September 2015. This document enshrines the authentic charism of the Order based on spirituality, charity and tradition, and enables it to function correctly in the twenty-first century for the benefit of its members and those whom they serve. The Constitutional Charter is a public document written in French, the official language of the Order.