In 1620, "Libro a naisurátan amin ti bagás ti Doctrina Cristiana" was written by Fr. Francisco Lopez, an "Ilokano Doctrina" the first Ilokano baybayin, based on the catechism written by Cardinal Belarmine. This is an important moment in the history of , because the krus-kudlít was introduced for the first time, which allowed writing final consonants. He commented the following on his decision: "The reason for putting the text of the Doctrina in Tagalog type... has been to begin the correction of the said Tagalog script, which, as it is, is so defective and confused (because of not having any method until now for expressing final consonants - I mean, those without vowels) that the most learned reader has to stop and ponder over many words to decide on the pronunciation which the writer intended." This krus-kudlit, or virama kudlit, did not catch on among users, however. Native experts were consulted about the new invention and were asked to adopt it and use it in all their writings. After praising the invention and showing gratitude for it, they decided that it could not be accepted into their writing because "It went against the intrinsic properties and nature that God had given their writing and that to use it was tantamount to destroy with one blow all the Syntax, Prosody and Orthography of their Tagalog language."