Rex W. Tillerson, the former chairman and chief executive of Exxon Mobil, was confirmed by the Senate on Wednesday to become the nation’s 69th secretary of state just as serious strains have emerged with important international allies.

The many votes against Mr. Tillerson’s confirmation made his selection among the most contentious for a secretary of state in recent history. In the past 50 years, the most contentious confirmations for secretary of state were those of Condoleezza Rice in 2005, who passed by a vote of 85 to 13, and Henry Kissinger in 1973, who was confirmed 78 to 7.

DEVELOPING STORY