Punctuation centuries meant that a standard system of punctuation was urgently required." The introduction of a standard system of punctuation has also been attributed to the Venetian printers Aldus Manutius and his grandson. They have been credited with popularizing the practice of ending sentences with the colon or full stop, inventing the semicolon, making occasional use of parentheses and creating the modern comma by lowering the virgule. By 1566, Aldus Manutius the Younger was able to state that the main object of punctuation was the clarification of syntax. By the 19th century, punctuation in the western world had evolved "to classify
Quotation mark punctuation should be written inside or outside the quotation marks; North American printing usually puts ending punctuation to the left of the closing quotation mark, whether it is part of the original quoted material or not, while styles elsewhere vary widely and have different rationales for placing it inside or outside, often a matter of house style. Regarding the aspect, there are two types of quotation marks: The closing single quotation mark is identical or similar in form (depending on the font) to the apostrophe and similar to the prime symbol. The double quotation mark is identical to the ditto