Short answers, pulled from the story.
The Latin alphabet is the writing system developed by ancient Romans to write Latin, standardized today as the ISO basic Latin alphabet with 26 letters. It is the most widely used writing system in the world, employed to write over 3,000 languages spoken by about 70% of the global population.
The Latin alphabet descended from the Etruscan alphabet, which itself evolved from the Cumaean Greek version of the Greek alphabet. That Greek alphabet derived from the Phoenician alphabet, which in turn drew from Egyptian hieroglyphs. The Etruscans, who ruled early Rome, passed their script to the Romans.
Y and Z were added after Rome conquered Greece in the 1st century BC. The two letters were adopted to write Greek loanwords and placed at the end of the alphabet, bringing the classical Latin inventory to 21 standard letters plus these 2 foreign additions.
Lowercase letter forms were introduced during the Middle Ages through scripts developed by Irish literati and the Carolingian minuscule derived from them. The classical Latin alphabet used only uppercase, or majuscule, forms.
The Latin script spread beyond Europe primarily through European colonialism and Christian missionary activity, which brought it to the Americas, sub-Saharan Africa, Australia, and Oceania. Linguists later extended its reach further by using it as the basis for transcription systems and written standards for non-European languages.
The core classical Latin alphabet had 21 letters. Y and Z were added from Greek after the Roman conquest of Greece in the 1st century BC. Later, during the Middle Ages and the Early Modern period, W was added as a ligature, and the conventions distinguishing I from J and U from V became established, producing the modern 26-letter set.