Simplify the following text for a Grade 11 native English-speaking person.
Original: In recent decades , an alternative doctrine known as `` Oneness '' has been espoused among various Pentecostal groups ( see below ) , but has been rejected by the remainder of Christendom .
Simplified: In recent past , another doctrine known as `` Oneness '' has gained credit amongst Pentecostal groups ( see below ) , but has been rejected by other Christians .