The holy five (PANJTAN PAK) includes Prophet Muhammad (sas), Hazrat Ali, Hazrat Fatima, Hazrat Hassan and Hazrat Hussain. The holy five in arabic is AHL AL BAYT (people of the house). The Panj Tan Pak are the five purified ones of the Prophets
family. It is supported by this verse of the Holy Quran. "Verily Allah desires to remove all blemish from you, O Ahl al-Bayt, and to purify you with a perfect purification." ( Quran 33:33 Allahu liyuthhiba AAankumu alrrijsa ahla albayti wayutahhirakum tatheeran ) When the above verse was revealed Prophet Muhammad spread his cloak over Hazrat Ali, Hazrat Fatima, Hazrat Hassan, and Hazrat Hussain (peace be upon them all) and declared "These are the members of my house and ALLAH (swt) has purified them all
Origins of Al-Baqi
Literally "al-Baqi" means a tree garden. It is also known as "Jannat al-Baqi" due to its sanctity, since in it are buried many of our Prophet's relatives and companions.
The first companion buried in al-Baqi was Uthman b. Madhoon who died on the 3rd of Sha'ban in the 3rd year of Hijrah. The Prophet (s) ordered certain trees to be felled, and in its midst, he buried his dear companion, placing two stones over the grave.