The Collaborative International Dictionary of English v.0.48:
Gladden \Glad"den\, v. t. [imp. & p. p. Gladdened; p. pr. & vb. n. Gladdening.] [See Glad, v. t.] To make glad; to cheer; to please; to gratify; to rejoice; to exhilarate. [1913 Webster] A secret pleasure gladdened all that saw him. --Addison. [1913 Webster]