Up to the latter period of Chosŏn dynasty, manuscripts in Korean alphabet(Hangeul) were widely spread. The catechism of Roman Catholicism, known that those persons just reading it were punished and owning it were automatically branded to be the object of persecution as well, was distributed publicly in the shape of manuscript and was even sold. How much rate of manuscript in Korean alphabet took in the catechism of Roman Catholicism at that time is well shown by Bibiliographie Coreenne(Paris, 1894), that lists up Catholic books, written by Mouris Courant's , French, for which he collected and classified books by himself and published. It shows clearly the trend that the manuscript in Korean alphabet among those books relating to Roman Catholicism took lion's share.
In the midst of such situation, the part of <Gyoyoseolon(敎要序論)> attracts attention. It not only explains the contents in detail but also mentions that <Gyoyoseolon >was also delivered by manuscript in Korean alphabet. So <Gyoyoseolon> written by Ferdinand Verbiest(南懷仁), proves the fact that manuscript in Korean alphabet was widely spread at that time and it is clear that this book was one of most important books to influence over the growth of Roman Catholicism greatly.
Korea Catholic church in the mid of 19C is analyzed to consist of just 7.89% of upper class and the common people, who took the rest of rate, including middle class and lower class partially. The reason why the believer of Roman Catholicism grew so rapidly could be explained through the fact that the common people and women available to read only Korean alphabet could have many chances to read the manuscript catechism in Korean alphabet, being widely distributed, including <Gyoyoseolon> and were likely to enter church on a large scale. This is the very effect of manuscript catechism in Korean alphabet, represented by <Gyoyoseolon>, and it's historical meaning.