Gray spent most of his life as a scholar in Cambridge, and only later in his life did he begin travelling again. Although he was one of the least productive poets (his collected works published during his lifetime amount to fewer than 1,000 lines), he is regarded as the foremost English-language poet of the mid-18th century. In 1757, he was offered the post of Poet Laureate, which he refused. Gray was so self-critical and fearful of failure that he published only thirteen poems during his lifetime. He once wrote that he feared his collected works would be "mistaken for the works of a flea." Walpole said that "He never wrote anything easily but things of Humour." Gray came to be known as one of the "Graveyard poets" of the late 18th century, along with Oliver Goldsmith, William Cowper, and Christopher Smart. Gray perhaps knew these men, sharing ideas about death, mortality, and the finality and sublimity of death.