It was narrated from Ibn ‘Abbas that the Messenger of Allah (ﷺ) stayed in Makkah for fifteen nights during the year of the Conquest, (during which time) he shortened his prayer.
Sunan Ibn Majah Book 5, Hadith 274
← Previous Hadith “The Messenger of Allah (ﷺ) stayed for nineteen days in which he shortened his prayer to two Rak’ah. So, whenever we stayed for nineteen days we would shorten our prayer to two Rak’ah, but if we stayed more than that we would pray four Rak’ah.”

Sunan Ibn Majah Book 5, Hadith 273 Next Hadith → “We went out with the Messenger of Allah (ﷺ) from Al-Madinah to Makkah, during which time we shortened our prayer to two Rak’ah, until we came back.” I asked: “How long did he stay in Makkah?” He said: “Ten (days).”

Sunan Ibn Majah Book 5, Hadith 275