Brihat Samhita
आसन्मघासु मुनयः शासति पृथ्वीं युधिष्ठिरे नृपतौ । षड्द्विकपञ्चद्वियुतः शककालस्तस्य राज्ञश्च ॥ १३-०३ ॥
During the reign of Yudhisthira, 2526 years before the commencement of Vikrama Śaka, the Seven Ṛṣis (Saptarṣi) were at the constellation of Maghā (Regulus).
english translation
AsanmaghAsu munayaH zAsati pRthvIM yudhiSThire nRpatau । SaDdvikapaJcadviyutaH zakakAlastasya rAjJazca ॥ 13-03 ॥
hk transliteration by Sanscript