Cross the Ts and dot the Is
Meaning
Pay close attention to every detail.
Usage
Used for proofreading or precise work.
Origin & History
Origins and dates here are approximate summaries. Many idioms have disputed or unknown origins, and not every date has been checked against a historical dictionary, so treat specific dates and stories as a starting point rather than a citation.
Copyists made sure their small t's and i's were complete.
Medieval scribes were known for their careful lettering.