grounded.

Originally: †widely told or narrated (obsolete). Later: widely or carefully preserved in writing or written accounts; clearly supported by…

Firmly or solidly established; of solid worth or value; of real significance, weighty; reliable… Of a reason, a cause, evidence.

Deeply or strongly founded; firmly fixed or established; resting upon a good basis. Chiefly figurative of immaterial things.

Of arguments, reasons, etc.: Having a sound or substantial foundation; based upon sound principles or indisputable facts.

Supported by much evidence; recorded in multiple sources.

Properly verified; supported by authoritative evidence; recorded in reliable sources.