Pope Francis celebrates his 85th birthday on Friday, a milestone made even more remarkable given the coronavirus pandemic, his summertime intestinal surgery and the weight of history: His predecessor retired at this age and the last pope to have lived any longer was Leo XIII over a century ago.Yet Francis is going strong, recently concluding a whirlwind trip to Cyprus and Greece after his pandemic-defying jaunts this year to Iraq, Slovakia and Hungary. He has set in motion an unprecedented two…