Either of the dates you describe could be the "trigger" date depending on the circumstances and which came first. As a general proposition, if an invention is "ready for patenting" AND it is offered for sale or sold, a "one year clock" in the United States starts ticking to file a patent application (though in many other countries requiring absolute novelty, you may have forfeited any patent chances).
Consult a patent attorney because the date you are concerned about is a "bar date" and could affect your ability to apply for a U.S. patent, foreign patents, etc., and affect the ultimate validity of a patent on the invention (you don't want to waste time and money on something already dedicated to the public"). Also be careful with the "last day" (your title question says, "1 year AFTER"). In general, it is prudent to file to file an application well BEFORE the one year anniversary of the trigger date for a variety of reasons.
See www.uspto.gov for more information. Start with FAQ.
The "on-sale bar" applies to the earliest disclosure of your invention, whether that was a sale, an offer for sale (marketing) or a publication (i.e., an article about your product even before you offered it for sale or sold it). Publication may be by any means that the public has access to (even obscure technical journals in the library).
Note that any new improvement after the sale will not be affected until its first publication/sale/offer. You may be able to obtain a patent on the improvement, but not the original concept. Think "car with wheels" sold for more than a year versus "car with wheels and a mirror" sold for less than a year. If it is important enough to have mirrors on the car, then that might be a valuable invention, but you won't be able to stop people from making, using, selling, offering for sale or importing "cars with wheels" only - although they can't add mirrors without infringing your invention.
This response does not create an attorney-client relationship and is for general information/educational purposes only. You should not rely on this response as legal advice and should always consult the attorney of your choice before taking legal action or to timely determine your legal rights.
I would say well before the one year anniversary of when you either offered it for sale or described the invention on a website. A website in any language anywhere in the world can be a printed publication if it describes the invention. The date that the website describing the invention was available for viewing anywhere in the world and in any language starts the one year clock ticking. Also, if the website offered the invented product for sale in the United States -- even if the website was hosted outside the United States -- that could also start the one year clock ticking. As for "official marketing", that term has no legal significance. A patent attorney would need a lot more information to advise you of when your one year clock started tickiing. But, I would run, not walk, to a competent patent attorney's office. Do not wait until what you think is the last minute.