If you had been around in 1902 and invited to the coronation of Queen Victoria’s son Edward VII (“Bertie” to his friends), you would have heard the premier performance of Sir Hubert Parry’s setting of Psalm 122 from the Church of England’s Book of Common Prayer, always known by its opening words: “I Was Glad.”
Psalm 122 in the Jewish Bible is one of a group of Psalms (songs) usually called “Psalms of ascent.” Scholars disagree on what exactly the word “ascent” refers, but the idea that’s usually listed first is that these psalms were sung by pilgrims on their way to Jerusalem to participate in various festivals in the Jewish calendar. Jerusalem is built on several hills (one of which had the name “Zion,” sometimes used to refer to Jerusalem as a whole), so you would indeed be ascending as you made your approach into the city.