Analysis Summary:

The article appears to be factually accurate. The key claims are verified by multiple reliable sources. There is no discernible bias in the reporting.

Detailed Analysis:

• Claim:** "Conclave to elect new pope to begin on 7 May, Vatican says" - Verification Source #2, #3, and #4 support this claim.
• Claim:** "The closed-door meeting will begin in the Sistine Chapel" - While not explicitly stated in all sources, Verification Source #1 and #5 imply this by discussing the conclave process. Verification Source #2 mentions the conclave, which is traditionally held in the Sistine Chapel.
• Claim:** "and will involve some 135 cardinals from across the world." - Verification Source #2 states "Some 135 cardinal electors - those under the age…". Verification Source #4 mentions "Roman Catholic cardinals".

Supporting Evidence/Contradictions:

• Verification Source #2, #3, and #4 all confirm the May 7 date for the start of the conclave.
• Verification Source #2 specifies that the 135 cardinals are "electors," implying they are eligible to vote.
• Verification Source #1, #2, #4, and #5 describe the conclave as a secretive process for electing a new Pope.
• No contradictions were found between the article and the verification sources.