It's true! It has been reported that Salmaan Al-Faarisee (may Allaah be pleased with him) lived 250 years. Some reports even say 350 years. [2] However, this seems unlikely due to the statement of the Prophet (sallallaahu 'alayhe wa sallam):

"The lifespans (of the members) of my Ummah are between 60 and 70 (years). Few live beyond this." [3]

A number of scholars rejected the reports about Salmaan al-Faarisee living 250 years, like Ath-Thahabee, since there are no connected chains to any of them. He suggested that Salmaan probably did not live past his seventies [2], and Allaah knows best.

[2] See Siyar A'laam An-Nubalaa' (1/555 of Ar-Risaalah).
[3] Saheeh Sunan At-Tirmithee (#3550), and even Al-Mubaarakfooree mentioned what was reported about Salmaan's lifespan in his explanation of this hadeeth. See Tuhfatul-Ahwathee (9/499).

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