During the Spanish times, family names were written down as:
Ramon Gregory Y Casiano,
with the mother's name written last.
Interpreted as: RAMON GREGORY "And" CASIANO.
With the "Y", or "AND", was later incorporated into the word, as in Ycasiano.
Instead of having the "Gregory" family name, Capt. Gen. Ramon Gregory Y Casiano's Filipino descent settled for the written form of Cpt./Gen. Ramon Gregory's documented full name.
It was the general's mother's maiden name that they were actually promoting down the clan's history.
And none of the earlier clan members had made corrective actions into this "typographical" error, or was it error in "pen-man-ship".
There were no typewriters during those time yet, it was the "plume" or the "quill pen".
The "Y" was later changed into the "I", for class "roll-call" purposes.
Most of the Gregory descendants, were almost always, the last class pupil, or student, to be called from the teacher's list.
This for having a family name that started with the letter "Y".
So down, along the clans family history, most of Gregory's decendants adopted the "I", instead of the "Y" for their family names to start with the "I", as in : "I" + "Casiano".
That was the story that I learned from my mom, she changed it while she was in school.
Her brothers, older than she is, had carried on the "Y", in the "Casiano" family name, but later changed it to an "I", for the purpose of "consistency", among the siblings.
Their father, Cesar Rivera Ycasiano, or more correctly, "CESAR RIVERA GREGORY", the eldest son of Dr. Santiago Bello Ycasiano, or more correctly, "DR. SANTIAGO BELLO GREGORY", used the "Y" with his surname, while his children with, Francisca Sarmiento Aguilar, had all adopted the "I", earlier or later on their lives.
The children of his sons, Mario, Adrio, Gumercindo, Serafin, and Rodobaldo, had all adopted the "I" into their surnames, again for the same reason, "they were almost always called last in the classroom".
Let it be known, that the true "surname" of this Filipino lineage from Blanca Casiano Gregory, through her son Capt./Gen. Ramon Casiano Gregory, is the surname "GREGORY", the surname of our great-great-grandfather.
And not : "Y CASIANO" nor "YCASIANO" nor "ICASIANO"
However, "reverting" to our true surname identity might cause a wave of legal complications.