The Messenger of Allah ﷺ used to observe thirteen rak'ahs of the night prayer. Five out of them consisted of Witr, and he did not sit, but at the end (for salutation). (Using translation from Muslim 737a)
كَانَ رَسُولُ اللهِ ﷺ «يُصَلِّي مِنَ اللَّيْلِ ثَلَاثَ عَشْرَةَ رَكْعَةً»