Remy Landau is quite correct in noting that after 2089, the next time Pesach will start on March 26 will be in the Gregorian Year 79431 (“Calendar calculations,” Oct 11). However, as the average length of the Jewish year is longer than that of the Gregorian year, over time, Jewish dates will tend to occur later in the Gregorian year. Eventually, as he indicates, a Jewish date will “wrap round” so that, having passed through the seasons, Pesach will once again begin on March 26. In doing so, the Jewish calendar will appear to have a lost a year relative to the Gregorian calendar. Accordingly, Pesach in Gregorian Year 79431 will be in the Jewish year 83190, and not 83191 as he states.