Complex sentence: Queen Māyā of Sakya (Māyādevī) was the birth mother of Gautama Buddha, the sage on whose teachings Buddhism was founded, and the sister of Mahāpajāpatī Gotamī, the first Buddhist nun ordained by the Buddha.
Split into simpler sentences: Queen Māyā of Sakya (Māyādevī) was the birth mother of Gautama Buddha, the sage on whose teachings Buddhism was founded. She was sister of Mahāpajāpatī Gotamī, the first Buddhist nun ordained by the Buddha.