After proclamation of the Constitution of the Kingdom of Poland, in 1815 significant changes concerning the order were introduced. The constitution preserved all Polish civilian and military orders, including The Order of Saint Stanislaus. On the basis of Alexander I's decree from the 1st December, 1815, the order was divided into four classes in order to extend granting decorations to a wider range of officials and citizens who „excell at serving the country and showing loyalty to the ruler”. The first class remained unchanged and was still worn on a ribbon put on through the right arm to the left side together with a star on the left breast. The second class was the same decoration worn on a narrower ribbon hanging from the neck, also with the same star. Class three – the decoration was smaller and worn on the neck, without a star. Finally, class four – a decoration without a star, worn on the breast „next to a button hole”. The decree also stated that „ noone will be honoured with the order of the higher class unless he is first awarded the lower order”. Soon another decree from the 16th December, 1816 specified the exact sums to be paid annually for the benefit of The Infant Jesus Hospital. In class one – 4 red zlotys, class 2 – 3 zlotys, class 3 – 2 zlotys, class 4 – 1 zloty. The same decree abolished the entrance fee of 25 red zlotys and cancelled all overdue payments.
In January, 1830 a detailed charter of The Royal Order of Saint Stanislau was proclaimed. It was signed by the tzar Nicholas I on the 2 (14) September 1829. The charter included „ various regulations concerning The Royal Order of the Saint Stanislau, issued at the time of its founding by the king Stanislaw August in 1765 as well as in later times, rules introduced by the king of Duchy of Warsaw. The division into four classes was preserved. The charter also specified merits and accomplishments for which all citizens regardless their ancestry could be awarded. Awarding the order of the first class to a person without noble ancestry resulted in automatical granting hereditary knighthood. All recipients of the order accepted the title of The Member of the Order of Saint Stanislau and were entitled to include the order in their coat of arms and seal stamps. Orders were to be bestowed for „great deeds of humanity”, for outstanding scientific, social, economical, cultural and charitable activity as well as all kinds of inventions and improvements particularly useful to the society and the state.
It was also decided that all officers and clarks both civilian and military can apply for the order if they particulary stand out, provided they received an „honourable mark”. An honourable mark after 35 years of service entitled to the order of the fourth class. Every Member of the Order of Saint Stanislau who was also awarded the honourable mark after 25 years of service was entitled to shorten the time required to retire. The knights of the first and second class could shorten the time of service by two years and those with orders of class 3 and 4 by one year. Alexander I granted the members an annual subsidy of 150 thousand zlotys. The sum was divided into so called „commandories” attached to the four classes of the order.
The members who were assigned to commandories had to wear a gold crown above the cross. The lists of candidates applying for the order submitted by the military authorities of the lower rank had to be assessed by the commander in chief and in case of civilian authorities – viceroy. The final decision was made by the monarch. Those distinguished with class 1 and 2 orders were given formal patents signed by the emperor and those with class 3 and 4 orders received extracts from the nomination. Fees of varied values had to be paid at the time of collecting the documents . Any court sentence involving dishonourable penalties deprived the awarded of all the priviledges and the rights to the order.
The orders from the period of 1815-1830 varied in size depending on their class. It should be mentioned however that even within the same class the sizes of crosses and stars could vary. During the uprising 1830-1831 the orders were not awarded. After its fall theemperor Nikolas I included the order into the system of Russian orders where it was given the eighth i.e. the last position.