Mahabharata 14.82.24

युधिष्ठिरस्याश्वमेधः परां चैत्रीं भविष्यतितत्रागच्छेः सहामात्यो मातृभ्यां सहितो नृप

yudhiṣṭhirasyāśvamedhaḥ parāṃ caitrīṃ bhaviṣyatitatrāgaccheḥ sahāmātyo mātṛbhyāṃ sahito nṛpa

Our plain-language meaning of this verse is waiting for scholar review.