In Browning’s poem, the speaker, a patriot is reminded of his past.
 
This is because his condition has has changed to exact opposite of what he had gone through just one year ago. At that time he enjoyed people’s trust and admiration which is now gone and he has now been adjudged a traitor and is sentenced to death. All the roses and fame have now been reduced to shame and death. Hence, the patriot reminds of his glorious past to ponder upon how short public memory is and how fickle human praise and glory are.